Wicked Witch of the Waste

The Great Plains has become the unconventional oil & gas industry’s dumping ground, prompting questions about the security and resilience of the bread basket and the underlying Ogalalla Aquifer

Back in December of 2016, FracTracker analyzed the growing link between injection wells that dispose fracking waste and “induced seismicity” [1], or human-caused earthquakes. Our compiled maps from this analysis (including Figure 1 below) show seismic activity in Kansas and Oklahoma along with Class II injection well volumes up through 2015. 

Figure 1. Earthquakes and Class II Injection Well Activity at the Kansas-Oklahoma Border

This link was given acute attention at that time as a result of the magnitude 5.8 earthquake in Pawnee, Oklahoma on September 3rd, 2016, followed closely by a 4.5 earthquake on November 1st.  The industry’s increased production of waste came home to roost 5 days later when a magnitude 5.0 quake struck a mile west of the “Cushing Hub,” the largest commercial crude oil storage center in North America. The Cushing Hub is capable of storing 54 million barrels of crude – the equivalent of 2.8 times the U.S. daily oil refinery capacity and 3.1 times the daily oil refinery capacity of all of North America.

Sunflower State of Affairs

Since we published this analysis and associated maps, Class II injection wells have been in the news several times across the Great Plains. An investigation by KSN News found that the Kansas Corporation Commission (KCC) improperly permitted over 2,000 Class II injection wells. The KCC stated that public comment periods for well proposals lasted just 15 days, instead of the correct number of 30 days. This amounts to 42% and 28% of the state’s active and total inventory of oil and gas waste receiving wells approved with inaccurate public notices.

Quail Oil & Gas LC’s Class II Salt Water Disposal (SWD) well, Morris County,
KS near Diamond Creek (Photo Courtesy of Karla jo Grimmett at South 500 photography)

According to Cindy Hoedel, a freelance journalist in Kansas, the KCC responded to the investigation findings… by ruling that no remedy was needed and closing the docket.”

Attorneys representing the Sierra Club maintain that improper permitting by the KCC continued into the Fall of 2018:

“The significance is they are choking us off in terms of giving us less and less time to try to mount a protest, to submit any kind of comment, and that’s a lot,” Cindy Hoedel, a Matfield Green resident who has complained about earthquakes in her area, said… “These notices get published in these tiny little newspapers, and sometimes it might take us 15 days before we find it”

As Ms. Hoedel wrote in an email when I asked her to comment on issues relating to Kansas’ Class II injection wells:

“The Republican controlled Kansas Legislature is trying to fend off several proposed bills that would reform the KCC (the regulatory body that oversees the permitting of Class II underground injection control wells). Citizen challenges of individual applications for disposal and EOR [enhanced oil recovery] wells continue, with the KCC moving more aggressively than in the past to dismiss protestants before a hearing is held. Some of these dismissals are being challenged in appellate court. The activists’ view is that EPA, the SWDA [Safe Water Drinking Act] and Congress clearly intend for the public to be able to participate in the regulatory process; instead, KCC has written regulations that are effectively barriers to participation… Activists have questions about the large number of EOR wells being applied for in Kansas and what their true purpose is, given the insignificant amounts of oil being produced compared to high volumes of injected fluids. Another concern is that the injection well earthquakes in Oklahoma and Kansas continue, yet KCC refuses to add regs that would address seismic risk in permit applications. There is also a problem with harassment of citizens exercising their right to protest – Scott Yeargain and I were both turned in to the Kansas AG’s office by a KCC staffer on the bogus claim that we were practicing law without a license because we helped explain the convoluted process to other protesters.”

Grapes of Wrath

Meanwhile, across the border, Oklahoma City and its surrounding suburbs have become the San Francisco of the Great Plains, with regular earthquake swarms (including many that exceed magnitude 4.0). According to Think Progress reporter Samantha Page, despite the damages and lawsuits caused by these earthquakes, “for years, the state was slow to respond, while Gov. Mary Fallin (R) and others questioned the link to human activity.” 

Eventually, by the end of 2016, the Oklahoma Corporation Commission responded by implementing a ‘traffic light’ protocol, in which operations are paused or stopped altogether following earthquakes of certain magnitudes. For a time, the EPA demanded a moratorium on disposal across Class II wells injecting into the Arbuckle formation in “high seismically active focus areas.”

Chad Warmington, president of the Oklahoma Oil and Gas Association, said that this response by the EPA is “a stellar example of the inefficiency of the federal government…It’s akin to a newspaper telling us today the football scores from games played 15 months ago.”

In reporting on the industry’s response, journalist Paul Monies, buried the lead when he pointed out the following in his second to last paragraph:

“Wastewater recycling remains an expensive option compared to the low costs of disposal wells in Oklahoma. While operators can inject wastewater into formations other than the Arbuckle, Hatfield said other formations don’t accept water as easily and are at shallower depths.”

The Map

Our second stab at mapping the scale and scope of Class II injection wells across the Great Plains is slightly different than our first effort in a few ways:

  1. This iteration includes Class II Salt Water Disposal (SWD) Injection Wells in Nebraska, Oklahoma, and Kansas on one map. Clicking on a well reveals its location, well name, operator, and the volume of wastewater disposed. Volumes are presented annually for Nebraska and monthly for 2011 to 2017 for Oklahoma and Kansas. We also present annual sums for Oklahoma from 2006 to 2010.
  2. The map shows Arkansas and Platte River Basin boundaries, which contain the entire inventory of OK, NE, and KS Class II wells.
  3. We’ve included Hydrologic Unit Codes, which when zoomed in to the map, identify sub-watersheds, and the Ogalalla Aquifer boundary, courtesy of the USGS’s Sharon Qi.
  4. Finally, we’ve includedUS Forest Service Robert G. Bailey’s Ecoregions to give a sense for the types of ecosystems threatened by the O&G industry’s demand for suitable waste disposal sites

View Map Full Screen | To view the legend on this map, click the “layers” icon on the top left of the screen

Table 1, below, breaks down the volumes of oil and gas wastewater disposed in Oklahoma, Kansas and Nebraska. Volumes are measured in million barrels, with one barrel equivalent to 42 gallons. The number of Class II SWD (salt water disposal) injection wells in these states is separated to show the total number of wells permitted verse the number of wells that were active (receiving waste).

Table 1. Class II injection well volumes in 2017

In total, 3,385,700,000 barrels of wastewater were disposed in 5,975 injection wells in these three states in 2017. The volume of wastewater disposed has increased in recent years (Table 2).

Table 2. Cumulative Class II injection well volumes to 2017, annual percent changes, and likely 2018 and 2027 volumes

In Table 2, the theoretical annual volumes for 2018 and 2027 are predictions based on the average of linear, exponential, and polynomial models.

The Kansas-Oklahoma Border

It is critical that we analyze the Great Plains fracking waste ecosystem across state lines. There are several reasons for this, including the proximity of Kansas’ most active Class II wells to the Oklahoma border (Figure 2) and the potential for the KCC to use enhanced oil recovery wells in Kansas to dispose of Oklahoma’s fracking waste.

Figure 2. Class II injection well volumes for 2017 along the Kansas-Oklahoma border.

Collaboration between front line communities, non-profits like FracTracker Alliance, and groups like the Kansas Water Advocacy Team (WAT) will be crucial to understanding the impacts of waste disposal writ large.  It seems like the “food vs energy” nexus has come to a head in the heart of the U.S. Bread Basket. We’ll continue to highlight and map the issues associated with this topic in the coming months and years.

Data Download Links

The following links contain the data used in the above tables and map, for use in excel and with Geographic Information Systems (GIS).

[1] To learn more about Induced Seismicity, read an exclusive FracTracker two-part series from former researcher with Virginia Tech Department of Geosciences, Ariel Conn: Part I and Part II.

Additionally, the USGS has created an Induced Earthquakes landing page as part of their Earthquake Hazards Program.

Power Plants & Other Facilities Now on Ohio Oil & Gas Map

Over the last few months we’ve been busy working on some updates to our Ohio Oil & Gas Map. Check out what we’ve added recently and explore the map below!

New: Power Plants & ATEX Pipeline

We now have the locations of eight of the credible natural gas power plants proposed in Ohio, along with the jobs they cite during construction and operations. We also now have a complete inventory of 118 existing power plants, including 25 natural gas facilities. Together, these plants would produce 7,660 megawatts, around 957 per facility.

Six of these plants are either in the heart of Ohio’s Utica Shale or within several miles of the 1,200+ mile Appalachia-to-Texas (ATEX) pipeline. ATEX was installed to transport 190,000 barrels per day (BPD) of natural gas liquids (NGLs) from the Marcellus and Utica region to the Texas and Louisiana Gulf Goast refinery corridor. The 360 mile segment of this pipeline that runs from Pennsylvania to south central Jackson County, Indiana is also now shown on the Ohio Oil & Gas Map.

Late Permitting Increases

Cumulative and Monthly Ohio Utica Hydraulic Fracturing Well Permits

Figure 1. Cumulative and monthly hydraulic fracturing well permits in Ohio’s Utica Shale

While many shale plays across the United States are experiencing a period of contraction (with low gas prices often cited as the primary reason), drilling activity in Ohio’s Utica Shale has been experiencing a slow and steady expansion. The region has seen more than 2,700 permitted wells as of the end of January 2017. Incidentally, roughly 59% of these wells are producing either oil or gas as of Q3-2016. For more information on that subject, explore our production map.

The permitting trajectory hit a low of 13-16 permits per month between February and January of 2016. Since the presidential election in November, however, permitting rates have more than doubled (Figure 1).

Ohio Oil & Gas Map

Ohio sits on the western edge of both the Utica and Marcellus Shale formations, but conditions are such that the Marcellus Shale is all but being ignored in Ohio. Explore our updated map of OH drilling activity and related facilities below:

View map fullscreen | How FracTracker maps work

Map Layers

The map above is made up of various datasets, from the location of permits to compressor stations. These “map layers” make up the legend. Below we describe each layer on the map, as well as the data source and date range.

Horizontal Marcellus Permits, Laterals
There have been 40+ permits issued for horizontal wells in Ohio’s Marcellus Shale.

Source:   Ohio Department of Natural Resources
Date Range:  December 2009 – Present

Horizontal Utica Permits
An aggregate of ODNR’s monthly cumulative Utica and Marcellus permits as well as a more detailed weekly Risk Based Data Management System (RBDMS) Microsoft Access inventory. At the present time Ohio is home to 2,160+ permitted Utica Wells with the wells broken out by status. Additionally this layer contains depth, water usage, sand usage, HCl, and Gelling Agent percentage for 249 wells based on data provided to FracFocus. Finally, we have incorporated production in various units from individual industry press releases and the ODNR annual report.

Source:   Ohio Department of Natural Resources
Date Range:  December 2009 – Present

Horizontal Utica Permits actual and straight line laterals
An aggregate of ODNR’s monthly cumulative Utica and Marcellus permits as well as a more detailed weekly Risk Based Data Management System (RBDMS) Microsoft Access inventory. At the present time we have straight line laterals for all drilled, drilling, and producing wells as well as actual PLAT laterals for 341 of the wells.

Source:   Ohio Department of Natural Resources
Date Range:  December 2009 – Present

High Volume Hydraulic Fracturing Gathering Lines
All gathering lines servicing Ohio’s inventory of High Volume Hydraulic Fracturing (HVHF) wells.

Source:   Herbert Hoover Foundation grant
Date Range:  December 2009 – 2015

High Volume Hydraulic Fracturing Well Pads
The well-pads of all Ohio’s drilled or producing High Volume Hydraulic Fracturing (HVHF) wells.

Source:   Herbert Hoover Foundation grant
Date Range:  December 2009 – 2015

High Volume Hydraulic Fracturing Well Pad’s Limits Of Disturbance (LOD)
Limits Of Disturbance (LOD) for all Ohio’s drilled or producing High Volume Hydraulic Fracturing (HVHF) well-pads.

Source: Herbert Hoover Foundation grant
Date Range:  December 2009 – 2015

Compressor Stations and Cracking Facilities
Boundaries of several confirmed High Volume Hydraulic Fracturing (HVHF) servicing cracking and compressor station facilities.

Source:   Herbert Hoover Foundation grant
Date Range:  December 2009 – 2015

Ohio Active Class II Injection Wells
This data speaks to the state’s “Active” Class II Injection wells able to accept hydraulic fracturing waste. There are 240+ Active Wells with 51 having yet to receive waste from hydraulic fracturing. For more on Ohio’s Class II Inventory in depth refer to our recent Ohio Fracking Waste Transport & Disposal Network article.

Source:   Ohio Department of Natural Resources
Date Range:  Historical to October, 2015

Earthquakes of >2.0 Magnitude
This data speaks to the state’s 258 earthquakes with current updates from the Ohio Seismic Network and historical quakes – all >2.0 magnitude. These data come from the department’s inventory. Additionally, we present Ohio earthquakes with <2.0 magnitude courtesy of Environment Canada’s Search the Earthquake Database platform.

Source: Ohio Department of Natural Resources, Division of Geological Survey, The Ohio Seismic Network
Date Range:  Historical to Present

AG Pruitt testifies before a congressional committee on issues surrounding energy and the environment

“Polluting Pruitt:” A Wolf to Guard the Hen House?

Guest article by Dakota Raynes, Co-Organizer of Stop Fracking Payne County (OK)

President Trump recently tapped Oklahoma Attorney General Scott Pruitt to head the Environmental Protection Agency (EPA), even though Pruitt is a self-proclaimed “leading advocate against the EPA’s activist agenda.” Pruitt is currently opposing investigation of Exxon Mobile’s handling of climate-change science based on the belief that climate change science is not yet settled and “debate should be encouraged in classrooms, public forums, and the halls of Congress.” Senate confirmation hearings regarding Pruitt’s nomination are currently ongoing – many questions have focused on Pruitt’s legacy as AG of OK and what that tells us about actions he might take as head of the EPA.

Pruitt’s Past as AG

Elected in 2010, Pruitt’s six-year tenure illuminates the full extent of the troubling stances he takes. For instance, he has fought against the overturn of DOMA, same-sex marriage rights, granting legal status to undocumented immigrants, the Affordable Care Act, access to safe and affordable birth control and abortions, and Dodd-Frank Wall Street reform. These actions demonstrate Pruitt’s inability to accept or implement procedures, policies, and programs supported by a majority of US residents, members of the nations’ highest courts, and even his own colleagues.

A Focus on Environmental Issues

More specifically related to environmental issues, he has openly criticized the EPA in congressional hearings and op-ed pieces. Due to his belief that the EPA frequently abuses its authority, Pruitt’s office has filed 14 antiregulatory lawsuits against the EPA. Investigative reporters uncovered that in 13 of these cases co-litigators included companies that had contributed significant amounts of money to Pruitt and/or Pruitt-affiliated political action committees (PACs). He also routinely joins lawsuits against other states. For example, Pruitt and five other Attorneys General challenged a California law banning the sale of eggs laid by hens living in cramped conditions, but a US District Judge ruled they lacked legal standing because they were representing the economic interests of a few industrial egg producers rather than the interests of their broader constituents.

Several such lawsuits are still pending, which legal experts and others claim presents a conflict of interest should Pruitt become the new Director of the EPA. When asked specifically about this issue during Senate confirmation hearings, Pruitt refused to recuse himself from the lawsuits, saying he would leave such a decision up to the EPA’s legal counsel team. Notably, across the course of his six-years as AG, Pruitt’s office has distributed more than 700 news releases announcing the office’s actions, his speeches and public appearances, and efforts to challenge federal regulations. More than 50 of these releases promoted the office’s efforts to sue the EPA, but not once has a release described actions the office has taken to enforce environmental laws or to hold violators accountable for their actions.

Potential Conflicts of Interest

In OK, Pruitt has made many choices, that when viewed together, strongly suggest that his loyalties reside with the industries that have donated hundreds of thousands of dollars to his election campaigns rather than with the people he is sworn to protect. Here is a short list of the most troubling examples:

  • Pruitt’s predecessor had filed suit against Tyson, Cargill, and a number of other poultry producers in OK due to inappropriate disposal of an estimated 300,000 tons of animal waste per year, which was causing toxic algae blooms along the Illinois River. But shortly after his election, Pruitt dropped the case, citing a need for more research. Some have questioned whether his decision was impacted by the fact that the poultry industry had donated at least $40,000 to his campaign that year.
  • He also quickly dismantled the Attorney General’s in-house environmental protection unit, a team of four attorneys and a criminal investigator, and replaced it with the state’s first “federalism unit,” which was created to litigate against overreach by the federal government, mostly the EPA. Pruitt has repeatedly made it clear that he believes states should handle environmental issues, regardless of the fact that environmental issues frequently cause problems that cross geopolitical boundaries such as state lines (OK’s induced seismicity issue1 is a key example, more information about induced seismicity can be found here).
  • In 2013, he created a coalition of 9 Attorneys General, major energy CEOs, and their lawyers and brought them all to OK for a strategizing session regarding how to stop government and citizen responses to the ills of the oil and gas industry; it was an all-expenses paid event funded by Mercatus, a right-wing think tank favored by the Koch brothers.
    1. Notably, the energy industry is Pruitt’s second largest campaign contributor. When he came up for re-election in 2013, he chose Harold Hamm (CEO of Continental Resources, one of the largest oil companies in OK) to co-chair his campaign. Shortly after winning reelection in 2014, Pruitt joined forces with key industry players including Oklahoma Gas and Electric and the Domestic Energy Producers Alliance (chaired by Hamm) to file several antiregulatory lawsuits, which include attempts to block the Clean Power Plan and Waters of the US rule.
    2. Pruitt has also served as leader of the Republican Association of Attorneys General, which has collected at least $4.2 million in donations from fossil-fuel related companies since 2013.
  • Recently, local investigative reporters discovered that Pruitt’s office failed to follow a state law requiring state agencies to disclose spending on outside attorneys. Their examination illuminated that Pruitt has spent more than $1 million on legal fees since FY2012 – a total that does not include costs directly related to lawsuits against the EPA or the Affordable Care Act.

Induced-Seismicity and Wastewater Disposal

OK Map of Recent Earthquakes for Pruitt article

Map of Oklahoma Class II Injection Wells and Volumes 2011 to 2015 (Barrels). Click image to explore a full screen, dynamic map.

Oklahoma recently became the earthquake capital of the world due to a phenomenon referred to as injection-induced seismicity. While OK has not historically been known as a seismically active area, thousands of tremors have shaken the state since the shale gas boom began.

Several researchers have used geospatial analysis to demonstrate how these quakes are caused by the high-pressure injection of oil and gas industry wastes such as the flowback and produced water created by the unconventional oil and gas production process known as hydraulic fracturing. The map above shows where injection wells (tan dots) are located and where earthquakes (green dots) occurred from 2011-2015.

Oklahomans have been harmed by the implicitly pro-fracking stance Pruitt has taken, as evidenced by his lack of action regarding induced seismicity – as well as air, water, and soil contamination due to oil and gas industry activities. Several people, including Johnson Bridgewater (Director of OK Chapter of the Sierra Club) have noted that:

There are various places where the attorney general’s office could have stepped in to fix this overall problem…Its job is to protect citizens. Other states were proactive and took these issues on…[yet] Pruitt has been completely silent in the face of a major environmental problem for the state and its taxpayers.

Specifically, the AG’s office could have responded to the legal question of whether the state could limit or ban transport of fracking-related wastewater, sent by other states for disposal in underground injection wells in OK.

He also did nothing to address the phenomenally low earthquake insurance claim approval rate; after the 5.8M quake shook Pawnee in September of 2016, 274 earthquake damage claims were filed but only 4 paid out. Estimates of statewide approval rates generally suggest that approximately 1% of claimants receive funds to aid repairs.

Lastly, there are a number of class action lawsuits against a variety of industry actors regarding earthquake damages, yet Pruitt’s office has not entered any of these as an intervenor even though AGs in other states have done so.

Pruitt not at fault?

Photo Credit: JIM BECKEL/The Oklahoman

Earthquake damage. Photo Credit: Jim Beckel/The Oklahoman

Pruitt was recently called out by investigative reporters who used open-records requests to reveal that letters, briefs, and lawsuits that he submitted were written in whole or in part by leading energy firms such as Devon (another of OK’s largest oil and gas companies). Pruitt’s response was that he had done nothing wrong, nothing even potentially problematic. Rather, he said, of course he was working closely with industry and isn’t that what he should be doing. Some would argue that as AG what he should be doing is working closely with the people of Oklahoma, especially those whose homes, lives, and livelihoods have crumbled under the weight of attempting to repair earthquake damage due to industry activities.

Historical AG Influence

It is important to remember, though, that what’s happening with Pruitt is not isolated. Rather, as several long-time reporters have noted, increased attention to developing beneficial relationships with AGs is a result of historical processes.

About 20 years ago more than 40 state AGs banded together to challenge the tobacco industry, which led to a historic $206 billion settlement decision. Later, Microsoft, the pharmaceutical industry, and the financial services industry each faced similar multistate challenges regarding the legality or illegality of particular business practices.

As some AGs began hiring outside law firms to investigate and sue corporations, industry leaders realized that AGs’ actions were far more powerful and immediate than those of legislative bodies. So, they began a heretofore unprecedented campaign to massively increase their influence at this level.

Several people have critiqued the ways in which such actions undermine democratic processes, prompt troubling questions about ethics, and negatively impact attorney generals’ abilities to fulfill their duties to the state and its residents.

A Mission at Risk

Those of us on the frontlines here in OK have seen just how powerful such coalitions can be, how much sway they can have on local and state officials, how they destabilize people’s faith and trust in the systems that are supposed to protect them, and how coalitions undercut people’s hope and desire to be civically engaged. The mission of the US Environmental Protection Agency is to protect human health and the environment. If confirmed to lead the EPA, it is very likely Pruitt will prioritize his relationships with industry over the health and welfare of the people and environment he’s directed to protect.


  1. To learn more about induced seismicity read an exclusive FracTracker two-part series from former VTSO researcher Ariel Conn: Part I and Part II. Additionally, the USGS has created an Induced Earthquakes landing page as part of their Earthquake Hazards Program.

Oklahoma and Kansas Class II Injection Wells and Earthquakes

By Ted Auch, Great Lakes Program Coordinator, FracTracker Alliance
In collaboration with Caleb Gallemore, Assistant Professor in International Affairs, Lafayette University

The September 3rd magnitude 5.8 earthquake in Pawnee, Oklahoma, is the most violent example of induced seismicity, or “man-made” earthquakes, in U.S. history, causing Oklahoma governor Mary Fallin to declare a state of emergency. This was followed by a magnitude 4.5 earthquake on November 1st prompting the Oklahoma Corporation Commission (OCC) and U.S. EPA to put restrictions on injection wells within a 10-mile radius of the Pawnee quake.

And then on Sunday, November 6th, a magnitude 5.0 earthquake shook central Oklahoma about a mile west of the Cushing Hub, the largest commercial crude oil storage center in North America capable of storing 54 million barrels of crude. This is the equivalent of 2.8 times the U.S. daily oil refinery capacity and 3.1 times the daily oil refinery capacity of all of North America. This massive hub in the North American oil landscape also happens to be the southern terminus of the controversial Keystone pipeline complex, which would transport 590,000 barrel per day over more than 2,000 miles (Fig. 1). Furthermore, this quake demonstrated the growing connectivity between Class II injection well associated induced seismicity and oil transport/storage in the heart of the US version of Saudi Arabia’s Ghawar Oil Fields. This increasing connectivity between O&G waste, production, and processing (i.e., Hydrocarbon Industrial Complex) will eventually impact the wallets of every American.

North American Oil Refinery Capacity, Pipelines, and Cushing, OK

Figure 1. The Keystone Pipeline would transport 590,000 bpd over more than 2,000 miles.

This latest earthquake caused Cushing schools to close. Magellan Midstream Partners, the major pipeline and storage facility operator in the region, also shut down in order to “check the integrity of our assets.” Compounding concerns about induced seismicity, the Cushing Hub is the primary price settlement point for West Texas Intermediate that, along with Brent Crude, determines the global price of crude oil and by association what Americans pay for fuel at the pump, at their homes, and in their businesses.

Given the significant increase in seismic activity across the U.S. Great Plains, along with the potential environmental, public health, and economic risks at stake, we thought it was time to compile an inventory of Class II injection well volumes. Because growing evidence points to the relationship between induced seismicity and oil and gas waste disposal, our initial analysis focuses on Oklahoma and Kansas. The maps and the associated data downloads in this article represent the first time Class II injection well volumes have been compiled in a searchable and interactive fashion for any state outside Ohio (where FracTracker has compiled class II volumes since 2010). Oklahoma and Kansas Class II injection well data are available to the public, albeit in disparate formats and diffuse locations. Our synthesis makes this data easier to navigate for concerned citizens, policy makers, and journalists.

Induced Seismicity Past, Present, and Future


Figure 2. Central U.S. earthquakes 1973-August 15, 2015 according to the U.S. Geological Survey (Note: Based on our analysis this exponential increasing earthquakes has been accompanied by a 300 feet per quarter increase in the average depth of earthquakes across Oklahoma, Kansas, and Texas).

Oklahoma, along with Arkansas, Kansas, Ohio, and Texas, is at the top of the induced seismicity list, specifically with regard to quakes in excess of magnitude 4.0. However, as the USGS and Virginia Tech Seismological Observatory (VTSO)[1] have recently documented, an average of only 21 earthquakes of magnitude 3.0 or greater occurred in the Central/Eastern US between 1973 and 2008. This trend jumped to an average of 99 between 2009 and 2013. In 2014 there were a staggering 659 quakes. The exponential increase in induced seismic events can be seen in Figure 2 from a recent USGS publication titled “High-rate injection is associated with the increase in U.S. mid-continent seismicity,” where the authors note:

“An unprecedented increase in earthquakes in the U.S. mid-continent began in 2009. Many of these earthquakes have been documented as induced by wastewater injection…We find that the entire increase in earthquake rate is associated with fluid injection wells. High-rate injection wells (>300,000 barrels per month) are much more likely to be associated with earthquakes than lower-rate wells.”


Figure 3. Average freshwater demand per hydraulically fractured well across four U.S. shale plays and the annual percent increase in each of those plays.

This trend suggests that induced seismicity is the new normal and will likely increase given that: 1) freshwater demand per hydraulically fractured well is rising all over the country, from 11-15% per year in the Marcellus and Bakken to 20-22% in the Denver and Midland formations, 2) the amount of produced brine wastewater parallels these increases almost 1-to-1, and 3) the unconventional oil and gas industry is using more and more water as they begin to explore the periphery of primary shale plays or in less productive secondary and tertiary plays (Fig. 3).


The September, 2016, Pawnee County Earthquake

This first map focuses on the September, 2016 Pawnee, OK Magnitude 5.8 earthquake that many people believe was caused by injecting high volume hydraulic fracturing (HVHF) waste into class II injection wells in Oklahoma and Kansas. This map includes all Oklahoma and Kansas Class II injection wells as well as Oklahoma’s primary geologic faults and fractures.

Oklahoma and Kansas Class II injection wells and geologic faults

View map fullscreenHow FracTracker maps work

Pawnee, Oklahoma 5.8 magnitude earthquake, September, 2016 & Active Class II Injection Wells

Figure 4. The September, 2016 Pawnee, Oklahoma 5.8M earthquake, neighboring active Class II injection wells, underlying geologic faults and fractures.

Of note on this map is the geological connectivity across Oklahoma resulting from the state’s 129 faults and fractures. Also present are several high volume wells including Territory Resources LLC’s Oldham #5 (1.45 miles from the epicenter, injecting 257 million gallons between 2011 and 2014) and Doyle #5 wells (0.36 miles from the epicenter, injecting 61 million gallons between 2011 and 2015), Staghorn Energy LLC’s Hudgins #1 well (1.43 miles from the epicenter, injecting 11 million gallons between 2011 and 2015 into the Red Fork formation), and Cooke Co Production Co.’s Laird #3-35 well (1.41 miles from the epicenter, injecting 6.5 million gallons between 2011 and 2015). Figure 4 shows a closeup view of these wells relative to the location of the Pawnee quake.

Class II Salt Water Disposal (SWD) Injection Well Volumes

This second map includes annual volumes of disposed wastewater across 10,297 Class II injection wells in Oklahoma between 2011 and 2015 (Note: 2015 volumes also include monthly totals). Additionally, we have included Oklahoma’s geologic faults and fractures for context given the recent uptick in Oklahoma and Kansas’ induced seismicity activity.

Annual volumes of class II injection wells disposal in Oklahoma (2011-2015)

View map fullscreenHow FracTracker maps work | Download map data

Oklahoma statistics for 2011 to 2015 (Table 1):

  1. Maximum volume to date (for a single Class II injection well): 105,979,598 barrels, or 4,080,214,523 gallons (68,003,574 gallons per month), for the New Dominion, LLC “Chambers #1” well in Oklahoma County.
  2. Total Volume to Date: 10,655,395,179 barrels or 410,232,714,392 gallons (6,837,211,907 gallons per month).
  3. Mean volume to date across the 10,927 Class II injection wells: approximately 975,144 barrels per well or 37,543,044 gallons (625,717 gallons per month).
  4. This map also includes 632 Class II wells injecting waste into the Arbuckle Formation which is believed to be the primary geological formation responsible for the 5.0 magnitude last week in Cushing.


Below is an inventory of monthly oil and gas waste volumes (barrels) disposed across 4,555 Class II injection wells in Kansas between 2011 and 2015. This map will be updated in the Spring of 2017 to include 2016 volumes. A preponderance of this data comes from 2015 with a scattering of volume reports across Kansas between 2011 and 2014.

Monthly Class II injection wells volumes in Kansas (2011-2015)

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Kansas statistics for 2015 (Table 1):

  1. Maximum volume to date (for a single Class II injection well): 9,016,471 barrels, or 347,134,134 gallons (28,927,845 gallons per month), for the Sinclair Prairie Oil Co. “H.J. Vohs #8” well in Rooks County. This is a well that was initially permitted and completed between 1949 and 1950.
  2. Total Volume to date: 1,060,123,330 barrels or 40,814,748,205 gallons (3,401,229,017 gallons per month).
  3. Mean volume to date across the 4,555 Class II injection wells: approximately 232,738 barrels per well or 8,960,413 gallons (746,701 gallons per month).

Table 1. Summary of Class II SWD Injection Well Volumes across Kansas and Oklahoma



Sum Average Maximum
No. of Class II
SWD Wells
Barrels Sum To Date Per Year Sum To Date Per Year
Kansas* 4,555 1.06 BB 232,738 9.02 MB
Oklahoma** 10,927 10.66 BB 975,143 195,029 105.98 MB 21.20 MB

* Wells in the counties of Barton (279 wells), Ellis (397 wells), Rooks (220 wells), Russell (199 wells), and Ness (187 wells) account for 29% of Kansas’ active Class II wells.

** Wells in the counties of Carter (1,792 wells), Creek (946 wells), Pontotoc (684 wells), Seminole (476 wells), and Stephens (1,302 wells) account for 48% of Oklahoma’s active Class II wells.


If the U.S. EPA’s Underground Injection Control (UIC) estimates are to be believed, the above Class II volumes account for 19.3% of the “over 2 billion gallons of brine…injected in the United States every day,” and if the connectivity between injection well associated induced seismicity and oil transport/storage continues to grow, this issue will likely impact the lives of every American.

Given how critical the Cushing Hub is to US energy security and price stability one could easily argue that a major accident there could result in a sudden disruption to fuel supplies and an exponential increase in “prices at the pump” that would make the 240% late 1970s Energy Crisis spike look like a mere blip on the radar. The days of $4.15 per gallon prices the country experienced in the summer of 2008 would again become a reality.

In sum, the risks posed by Class II injection wells and are not just a problem for insurance companies and residents of rural Oklahomans and Kansans, induced seismic activity is a potential threat to our nation’s security and economy.


FracTracker Induced Seismicity Infographic (print quality)

Oklahoma Class II SWD Injection Well Annual Volumes 2011 to 2015 (Barrels)

Kansas Class II SWD Injection Well Monthly Volumes 2011 to 2015 (Barrels)


[1] To learn more about Induced Seismicity read an exclusive FracTracker two-part series from former VTSO researcher Ariel Conn: Part I and Part II. Additionally, the USGS has created an Induced Earthquakes landing page as part of their Earthquake Hazards Program.

Earthquake damage photo from Wikipedia

The Science Behind OK’s Man-made Earthquakes, Part 2

By Ariel Conn, Seismologist and Science Writer with the Virginia Tech Department of Geosciences

Oklahoma has made news recently because its earthquake story is so dramatic. The state that once averaged one to two magnitude 3 earthquakes per year now averages one to two per day. This same state, which never used to be seismically active, is now more seismically active than California. In terms of understanding the connection between wastewater disposal wells and earthquakes, though, it may be more helpful to look at other states first. Let us explore this issue further in Man-made Earthquakes, Part 2.

How other states handle induced seismicity

In 2010 and 2011, Arkansas experienced a swarm of earthquakes near the town of Greenbrier that culminated in a magnitude 4.7 earthquake. Officials in Arkansas ordered a moratorium on all disposal wells in the area, and earthquake activity quickly subsided.

In late 2011, Ohio experienced small earthquakes near a disposal well that culminated in a magnitude 4 earthquake that shook and startled residents. The disposal well was shut down, and the earthquakes subsided. Subsequent research into the earthquake confirmed that the disposal well in question had, in fact, triggered the earthquake. A swarm of earthquakes last year in Ohio shut down another well, and again, after the wastewater injection ceased, the earthquakes subsided.

Similarly in Kansas, after two earthquakes of magnitudes 4.7 and 4.9 shook the state in late 2014, officials ordered wells in two southern counties to decrease the volume of water injected into the ground. Again, earthquake activity quickly subsided.

A seismologist’s toolbox

A favorite saying among scientists is that correlation does not equal causation, and it’s easy to apply that phrase to the correlations seen in Ohio, Arkansas, and Kansas. Yet scientists remain certain that wastewater disposal wells can trigger earthquakes. So what are some of the techniques they use to come to these conclusions? At the Virginia Seismological Observatory (VTSO), two of the tools we used to determine a connection were cross-correlation programs and beach ball diagrams.


The VTSO research, which was funded by the National Energy Technology Laboratory, looked specifically at earthquake swarms that have popped up a couple times near a wastewater disposal well in West Virginia. We used a cross-correlation program to distinguish earthquakes that were likely triggered by the nearby well from events that might be natural or related to mining activity.

A seismic station records all of the vibrations that occur around it as squiggly lines. When an earthquake wave passes through, its squiggly lines take on a specific shape, known as a waveform, that seismologists can easily recognize (as an example, the VTSO logo in Fig. 1 was designed using a waveform from one of West Virginia’s potentially induced earthquakes.)

Virginia Tech Seismological Observatory logo

Figure 1. Virginia Tech Seismological Observatory logo w/waveform

For naturally occurring earthquakes, the waveforms will have some variation in shape because they come from different faults in different locations. When an injection well triggers earthquakes, it typically activates faults that are within close proximity, resulting in greater similarities between waveforms. A cross-correlation program is simply a computer program that can run through days, weeks, or months of data from a seismometer to find those similar waveforms. When matching waveforms indicate that earthquake activity is occurring near an injection well – and especially in regions that don’t have a history of seismic activity – we can conclude the earthquakes are triggered by human activity.

Beach Balls

Any earthquake fault, whether it’s active or ancient, is stressed to its breaking point. The difference is that, in places like California that are active, the natural forces against the faults often change, which triggers earthquakes. Ancient faults are still highly stressed, but the ground around them has become more stabilized. However at any point in time, if an unexpected force comes along, it can still trigger an earthquake.

Beach ball diagrams of 16 of the largest earthquakes in Oklahoma in 2014, all showing similar focal mechanisms, which is indicative of induced seismicity.

Figure 2. Beach ball diagrams of 16 of the largest earthquakes in Oklahoma in 2014, all showing similar focal mechanisms, which is indicative of induced seismicity.

Earthquake faults don’t all point in the same direction, which means different forces will affect faults differently. Depending on their orientation, some faults might shift in a north-south direction, some might shift in an east-west direction, some might be tilted at an angle, while others are more upright, etc. Seismologists use focal mechanisms to describe the movement of a fault during an earthquake, and these focal mechanisms are depicted by beach ball diagrams (Figure 2). The beach ball diagrams look, literally, like black and white beach balls. Different quadrants of the “beach ball” will be more dominant depending on what type of fault it was and how it moved (See USGS definition of Focal Mechanisms and the “beach ball” symbol).

When an earthquake is triggered by an injection well, it means that the fluid injected into the ground is essentially the straw that broke the camel’s back. Earthquake theory predicts that the forces from an injection well won’t trigger all faults, but only those that are oriented just right. Since we expect that only certain faults with just the right orientation will get triggered, that means we also expect the earthquakes to have similar focal mechanisms, and thus, similar beach ball diagrams. And that’s exactly what we see in Oklahoma.

Cross-correlation programs and beach ball diagrams are only two tools we used at the VTSO to confirm which earthquakes were induced, but seismologists have many means of determining if an earthquake is induced or natural.

Limitations of science?

With so much strong scientific evidence, why can people in industry still claim there isn’t enough science to officially confirm that an injection well triggered an earthquake? In some cases, these claims are simply wrong. In other cases, though, especially in Oklahoma, the problem is that no one was monitoring the disposal wells and the earthquakes from the start. Well operators were not required to publicly track the volumes of water they injected into wells until recently, and no one monitored for nearby earthquake activity. The big problem is not a lack of scientific evidence, but a lack of data from industry to perform sufficient research. Scientists need information about the history, volume, and pressure of fluid injection at a disposal well if they’re to confirm whether or not earthquakes are triggered by it. Often, that information is proprietary and not publically available, or it may not exist at all.

At this point though, two other factors make direct correlations between injection wells and earthquakes in Oklahoma even more difficult:

  1. So many wells have injected signficiant volumes of water in close enough proximity that pointing a finger at a specific well is more challenging.
  2. A large number of wells have injected water for so many years, that the earthquakes are migrating farther and farther from their original source. Again, pointing a finger at a specific well gets harder with time.

What we know

We know what induced seismicity is and why it occurs. We know that if a wastewater injection well disposes of large volumes of fluids deep underground in a region that has existing faults, it will likely trigger earthquakes. We know that if a region previously had few earthquakes, and then sees an uptick in earthquakes after wastewater injection begins, the earthquakes are likely induced. We know that if we want to understand the situation better, we need more seismic stations near disposal wells so we can more accurately monitor the area for seismicity both before and after the well becomes active.

What don’t we know?

We don’t know how big an induced earthquake can get. Oklahoma’s largest earthquake, which was also the largest induced earthquake ever recorded in the United States, was a magnitude 5.6. That’s big enough to cause millions of dollars of damage. Worldwide, the largest earthquake suspected to be induced occurred near the Koyna Dam in India, where a magnitude 6.3 earthquake killed nearly 200 people in 1967.

Can an earthquake that large occur in the central U.S.? The best guess right now: yes.

Seismologists suspect that an induced earthquake could get as big as the size of the fault. If a fault is big enough to trigger a magnitude 7 or 8 earthquake, then that is potentially how large an induced earthquake could be. In the early 1800s, three earthquakes between magnitudes 7 and 8 struck along the New Madrid Fault Zone near St. Louis, Missouri. Toward the end of the 1800s, a magnitude 7 earthquake shook Charleston, South Carolina. In those two areas, injection wells could potentially trigger very large earthquakes.

We have no historic record of earthquakes that large in Oklahoma, so right now, the best guess is that the largest an earthquake could get there would be between a magnitude 6 and 6.5. That would be big enough to cause significant damage, injuries, and possibly death.

The solution

What’s the take-home message from all of this?

  • First, the science exists to back up the conclusion that wastewater injection wells trigger earthquakes.
  • Second, if we want to get a better feel for which wells are more problematic, we need funding, seismic stations, and staff to monitor seismic activity around all high-volume injection wells, along with a history of injection times, volumes and pressures at the well.
  • Third, this is a problem that, if left unchecked, has the potential to result in major damage, incredible expense, and possibly loss of life.

Induced earthquakes are a real phenomenon. While more research is necessary to help us better understand the intricacies of these events and to identify correlations in complex cases, the general cause of the earthquake swarms in Oklahoma and other states is not a mystery. They are man-made problems, backed up by decades of scientific research. They have the potential to create significant damage, but we have the wherewithal to prevent them. We don’t need to go to the extreme of shutting down all wells, but rather, we just need to be able to monitor the wells and ensure that they don’t trigger earthquakes. If a well does trigger an earthquake, then at that point, the well operators can either experiment with significantly decreasing the volume of water that’s injected, or the well can be shut down completely. Understanding and acknowledging the connection between injection wells and earthquakes will make induced seismicity a much easier problem to solve.

The Science Behind OK’s Man-made Earthquakes, Part 1

By Ariel Conn, Seismologist and Science Writer with the Virginia Tech Department of Geosciences

On April 21, the Oklahoma Geological Survey issued a statement claiming that the sharp rise in Oklahoma earthquakes — from only a couple per year to thousands — was most likely caused by wastewater disposal wells associated with major oil and gas plays. This is huge news after years of Oklahoma scientists hesitating to place blame on an industry that provides so many jobs.

Now, seismologists from around the country — including Oklahoma — are convinced that these earthquakes are the result of human activity, also known as induced or triggered seismicity. Yet many people, especially those in the oil industry, still refute such an argument. Just what is the science that has seismologists so convinced that the earthquakes are induced and not natural?

Hidden Faults

Over the last billion years (give or take a couple hundred million), colliding tectonic plates have created earthquake zones, just as we see today in California, Japan, Chile and Nepal. As geologic processes occurred, these zones shifted and moved and were covered up, and the faults that once triggered earthquakes achieved a state of equilibrium deep in the basement rocks of the earth’s crust. But the faults still exist. If the delicate balance that keeps these fault systems stable ever shifts, the ancient faults can still move, resulting in earthquakes. Because these inactive faults are so deep, and because they can theoretically exist just about anywhere, they’re incredibly difficult to map or predict – until an earthquake occurs.

Thanks to historic reports of earthquakes in the central and eastern United States, we know there are some regions, far away from tectonic plate boundaries, that occasionally experience large earthquakes. Missouri and South Carolina, for example, suffered significant and damaging earthquakes in the last 200 hundred years, yet these states lie nowhere near a plate boundary. We know that fault zones exist in these locations, but we have no way of knowing about dormant faults in regions of the country that haven’t experienced earthquakes in the last couple hundred years.

What is induced seismicity?

As early as the 1930s, seismologists began to suspect that extremely large volumes of water could impact seismic activity, even in those regions where earthquakes weren’t thought to occur. Scientists found that after certain reservoirs were built and filled with water, earthquake swarms often followed. This didn’t happen everywhere, and when it did, the earthquakes were rarely large enough to be damaging. These quakes were large enough to be felt, however, and they represented early instances of human activity triggering earthquakes.[1]

Research into induced seismicity really picked up in the 1960s. The most famous example of man-made earthquakes occurred as a result of injection well activity at the Rocky Mountain Arsenal. The arsenal began injecting wastewater into a disposal well 12,000 feet deep in March of 1962, and by April of that year, people were feeling earthquakes. Researchers at the arsenal tracked the injections and the earthquakes. They found that each time the arsenal injected large volumes of water (between 2 and 8 million gallons per month, or 47,000 to 190,000 barrels), earthquakes would start shaking the ground within a matter of weeks (Figure 1).

Rocky Mountain Arsenal fluid injection correlated to earthquake frequency

Figure 1. Rocky Mountain Arsenal fluid injection correlated to earthquake frequency

South Carolina experienced induced earthquakes after filling a reservoir

Figure 2. South Carolina experienced induced earthquakes after filling a reservoir

When the injections ended, the earthquakes also ceased, usually after a similar time delay, but some seismicity continued for a while. The well was active for many years, and the largest earthquake thought to be induced by the injection well actually occurred nearly a year and a half after injection officially ended. That earthquake registered as a magnitude 5.3. Scientists also noticed that over time, the earthquakes moved farther and farther away from the well.

Research at a reservoir in South Carolina produced similar results; large volumes of water triggered earthquake swarms that spread farther from the reservoir with time (Figure 2).

When people say we’ve known for decades that human activity can trigger earthquakes, this is the research they’re talking about.

Why now? Why Oklahoma?

Class II Injection Well. Photo by Lea Harper

Injection Well in Ohio. Photo by Ted Auch

Seismologists have known conclusively and for quite a while that wastewater injection wells can trigger earthquakes, yet people have also successfully injected wastewater into tens of thousands of wells across the country for decades without triggering any earthquakes. So why now? And why in Oklahoma?

The short answers are:

  • At no point in history have we injected this much water this deep into the ground, and
  • It’s not just happening in Oklahoma.

One further point to clarify: General consensus among seismologists is that most of these earthquakes are triggered by wastewater disposal wells and not by hydrofracking (or fracking) wells. That may be a point to be contested in a future article, but for now, the largest induced earthquakes we’ve seen have been associated with wastewater disposal wells and not fracking. This distinction is important when considering high-pressure versus high-volume wells. A clear connection between high-pressure wells and earthquakes has not been satisfactorily demonstrated in our research at the Virginia Tech Seismological Observatory (VTSO) (nor have we seen it demonstrated elsewhere, yet). High-volume wastewater disposal wells, on the other hand, have been connected to earthquakes.

At the VTSO, we looked at about 8,000 disposal wells in Oklahoma that we suspected might be connected to induced seismicity. Of those, over 7,200 had maximum allowed injection rates of less than 10,000 barrels per month, which means the volume is low enough that they’re unlikely to trigger earthquakes. Of the remaining 800 wells, only 300 had maximum allowed injection rates of over 40,000 barrels per month — and up to millions of barrels per year for some wells. These maximum rates are on par with the injection rates seen at the Rocky Mountain Arsenal, and our own plots indicate a correlation between high-volume injection wells and earthquakes (Figure 3-4).

Triangles represent wastewater injection wells scaled to reflect maximum volume rates. Wells with high volumes are located near earthquakes.

Figure 3. Triangles represent wastewater injection wells scaled to reflect maximum volume rates. Wells with high volumes are located near earthquakes.

Triangles represent wastewater injection wells scaled to reflect maximum pressure. Wells with high pressures are not necessarily near earthquakes.

Figure 4. Triangles represent wastewater injection wells scaled to reflect maximum pressure. Wells with high pressures are not necessarily near earthquakes.

This does not mean that all high-volume wells will trigger earthquakes, or that lower-volume wells are always safe, but rather, it’s an important connection that scientists and well operators should consider.

Starting in 2008 and 2009, with the big oil and gas plays in Oklahoma, a lot more fluid was injected into a lot more wells. As the amount of fluid injected in Oklahoma has increased, so too have the number of earthquakes. But Oklahoma is not the only state to experience this phenomenon. Induced earthquakes have been recorded in Arkansas, Colorado, Kansas, New Mexico, Ohio, West Virginia and Texas.

In the last four years, Arkansas, Kansas, Ohio and Texas have all had “man-made” earthquakes larger than magnitude 4, which is the magnitude at which damage begins to occur. Meanwhile, in that time period, Colorado experienced its second induced earthquake that registered larger than magnitude 5. Oklahoma may have the most induced and triggered earthquakes, but the problem is one of national concern.


[1] Induced seismicity actually dates back to the late 1800s with mining, but the connection to high volumes of fluid was first recognized in the 1930s. However, the extent to which it was documented is unknown.

Class II Oil and Gas Wastewater Injection and Seismic Hazards in CA

By Kyle Ferrar, CA Program Coordinator, FracTracker Alliance Shake Ground Cover

In collaboration with the environmental advocacy groups Earthworks, Center for Biological Diversity, and Clean Water Action, The FracTracker Alliance has completed a proximity analysis of the locations of California’s Class II oil and gas wastewater injection wells to “recently” active fault zones in California. The results of the analysis can be found in the On Shaky Ground report, available for download at

Production of oil and natural gas results in a large and growing waste stream. Using current projections for oil development, the report projects a potential 9 trillion gallons of wastewater over the lifetime of the Monterey shale. In California the majority of wastewater is injected deep underground for disposal in wells deemed Class II wastewater injection.  The connection between seismic activity and underground injections of fluid has been well established, but with the current surge of shale resource development the occurrence of earthquakes in typically seismically inactive regions has increased, including a recent event in Ohio covered by the LA Times.   While both hydraulic fracturing and wastewater injection wells have been linked to the induction of seismic activity, the impacts of underground injection wells used for disposal are better documented and linked to larger magnitude earthquakes.

Therefore, while hydraulic fracturing of oil and gas wells has also been documented to induce seismic activity, the focus of this report is underground injection of waste fluids.

Active CA Faults

A spatial overview of the wastewater injection activity in California and recently active faults can be viewed in Figure 1, below.

Figure 1. California’s Faults and Wastewater Injection Wells. With this and all maps on this page, click on the arrows in the upper right hand corner of the map to view it fullscreen and to see the legend and more details.

The focus of the On Shaky Ground report outlines the relationship between does a thorough job reviewing the literature that shows how the underground injection of fluids induces seismic activity.  The proximity analysis of wastewater injection wells, conducted by The FracTracker Alliance, provides insight into the spatial distribution of the injection wells.  In addition, the report M7.8 earthquake along the San Andreas fault could cause 1,800 fatalities and nearly $213 billion in economic damages.2  To complement the report and provide further information on the potential impacts of earthquakes in California, FracTracker created the maps in Figure 2 and Figure 3.

Shaking Assessments

Figure 2 presents shaking amplification and shaking hazards assessments. The dataset is generated from seismic evaluations.  When there is an earthquake, the ground will amplify the seismic activity in certain ways.  The amount of amplification is typically dependent on distance to the earthquake event and the material that comprises the Earth’s crust.  Softer materials, such as areas of San Francisco built on landfills, will typically shake more than areas comprised of bedrock at the surface.  The type of shaking, whether it is low frequency or high frequency will also present varying hazards for different types of structures.  Low frequency shaking is more hazardous to larger buildings and infrastructure, whereas high frequency events can be more damaging to smaller structure such as single family houses.  Various assessments have been conducted throughout the state, the majority by the California Geological Survey and the United States Geological Survey.

Figure 2. California Earthquake Shaking Amplification and Class II Injection Wells

Landslide Hazards

Below, Figure 3. Southern California Landslide and Hazard Zones expands upon the map included in the On Shaky Ground report; during an earthquake liquefaction of soil and landslides represent some of the greatest hazards.  Liquefaction refers to the solid earth becoming “liquid-like”, whereas water-saturated, unconsolidated sediments are transformed into a substance that acts like a liquid, often in an earthquake. By undermining the foundations of infrastructure and buildings, liquefaction can cause serious damage. The highest hazard areas shown by the liquefaction hazard maps are concentrated in regions of man-made landfill, especially fill that was placed many decades ago in areas that were once submerged bay floor. Such areas along the Bay margins are found in San Francisco, Oakland and Alameda Island, as well as other places around San Francisco Bay. Other potentially hazardous areas include those along some of the larger streams, which produce the loose young soils that are particularly susceptible to liquefaction.  Liquefaction risks have been estimated by USGS and CGS specifically for the East Bay, multiple fault-slip scenarios for Santa Clara and for all the Bay Area in separate assessments.  There are not regional liquefaction risk estimate maps available outside of the bay area, although the CGS has identified regions of liquefaction and landslide hazards zones for the metropolitan areas surrounding the Bay Area and Los Angeles.  These maps outline the areas where liquefaction and landslides have occurred in the past and can be expected given a standard set of conservative assumptions, therefore there exist certain zoning codes and building requirements for infrastructure.

Figure 3. California Liquefaction/Landslide Hazards and Class II Injection Wells

Press Contacts

For more information about this report, please reach out to one of the following media contacts:

Alan Septoff
(202) 887-1872 x105
Patrick Sullivan
Center for Biological Diversity
(415) 632-5316
Andrew Grinberg
Clean Water Action
(415) 369-9172


  1. Arbelaez, J., Wolf, S., Grinberg, A. 2014. On Shaky Ground. Earthworks, Center for Biological Diversity, Clean Water Action. Available at
  2. Jones, L.M. et al. 2008. The Shakeout Scenario. USGS Open File Report 2008-1150. U.S. Department of the Interior, U.S. Geological Survey.