Photograph of building damage near Los Angeles 1994  © Daniel FriedmanManmade Earthquake Causes, Locations, & Damage

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Manmade earthquakes around the world: this article describes several known and possible causes of man-made earthquakes around the world and provides links to and citations of expert sources on both manmade earthquakes and the unclamping effects of pressure changes in the earth or in rock formations that may explain an increase in earthquakes in some areas as well as certain severe earthquakes that have occurred around the world.

For building professionals and building owners/occupants, the apparent increase in earthquakes traced to human activity must be considered when evaluating both existing building damage and in predicting future losses or safety hazards.

The page top illustration is a USGS map showing the epicenter of a recent earthquake near Oklahoma City in the U.S. - an earthquake that may have been triggered by the cumulative effects of pressure-well disposal of oil drilling wastewater, though other causes may also be considered.

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Manmade Earthquake Damage Sources: mining, oil or gas extraction & hydraulic fracturing or "fracking" activities can lead to earthquakes

Earthquake damage, Northridge, Los Angeles (C) Daniel FriedmanIn diagnosing earthquake type damage to buildings and their structures or foundations, note that even in areas that are not considered earthquake zones earthquakes may occur and may be traced to human activities.

Photo at left: building damage in Los Angeles examined by the author [DF] following California's Northridge Earthquake of 1994. This building collapse was not due to a man-made earthquake, but ...

Significant earthquakes are increasingly occurring within the continental interior of the United States, including five of moment magnitude (Mw) ≥ 5.0 in 2011 alone. - Keranen et als (2013) [27]

When a stress fracture is unclamped, areas of rock formation may move or "slip" past one another causing earthquakes of varying magnitude. [12] Ross Stein at the USGS offers this crisp explanation of the effects of unclamping and its relationship to earthquakes: [13][14][15]

An earthquake alters the shear and normal stress on surrounding faults. New evidence strengthens the hypothesis that such small, sudden stress changes cause large changes in seismicity rate. Rates climb where the stress increases (aftershocks) and fall where the stress drops. Both increases and decreases in seismicity rate are followed by a time-dependent recovery. When stress change is translated into probability change, seismic hazard is seen to be strongly influenced by earthquake interaction. - Ross Stein (1999) [13] 

King (2001) reported similarly on "fault interaction by elastic stress changes" [18] Drilling and mining activities are also traced to a different type of earth movement: sinkhole formation in many areas of the world.

Details and examples are at SINKHOLES, WARNING SIGNS. But in addition, even if sinkholes are not appearing over or close to drilling and mining sites, oil drilling and in particular the disposal of oil-drilling wastewater by forced injection into underground wells may cause earthquakes of sufficient magnitude to damage buildings by causing changes in underground rock formation pressures, a process referred to as unclamping of pre-existing stress-faults.

Manmade Earthquakes in Oklahoma and Other Parts of the United States

USGS scientists have found that at some locations the increase in seismicity coincides with the injection of wastewater in deep disposal wells. Much of this wastewater is a byproduct of oil and gas production and is routinely disposed of by injection into wells specifically designed and approved for this purpose.

... It has long been understood that earthquakes can be induced by impoundment of water in reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids into underground formations. - USGS (2013) [26]

In December 2013 The New York Times reported a significant increase in the frequency of earthquakes in and around Oklahoma city, an area with a long history of extensive oil drilling and exploration.

The Times explained that the area, not previously known to be earthquake prone, had historically experienced about 50 earth tremors annually, almost all "minor". But in 2013 the area experienced more than 2600 earthquakes including 87 in the second week of December of 2013. In addition to the 520% increase in earthquake frequency in the past year, in 2011 the area suffered a 5.6 magnitude earthquake, the largest ever recorded in Oklahoma. [12]

The Times article reported that disposal wells pose the greatest risk of causing these unclamping type earthquakes and that the cumulative effects of years of disposal of oil drilling wastewater into pressure fed wells may have reached some cumulative tipping point. The article pointed out that there could be other explanations as well, and Toda and Stein reported on the cumulative effects of earthquakes as a force that "untoggles" earth movement.[19] And Hayes, U.S. Department of Interior observed in 2012

USGS’s studies do not suggest that hydraulic fracturing, commonly known as “fracking,” causes the increased rate of earthquakes. USGS’s scientists have found, however, that at some locations the increase in seismicity coincides with the injection of wastewater in deep disposal wells. [28]

Catalog of Recent Manmade Earthquakes Around the World & Unclamping Effects

The New York Times reporter, Henry Fountain, included a mini catalog of locations where injection wells or other human activities had the effect of unclamping old faults and leading to earthquakes that we have expanded a bit from other sources.

  • Australia, 1989 Earthquake: cumulative effect of removal of billions of tons of coal
  • Canada: British Columbia, possible effects of fracking (hydraulic fracturing by injection of high pressure liquid into shale rock to obtain oil or gas*)
  • China, Sichuan Province, 2008 Earthquake: weight of water behind a new dam [16]
  • England: possible effects of fracking *
  • Italy: "... If previous ruptures unclamp the fault planes of subsequent earthquakes, fluid flow can play a dominant role in promoting earthquakes during the seismic sequence." (the 1997 Umbria / March earthquake) [21]
  • Netherlands: In March 2013 The New York Times reported on new earthquakes occurring at Loppersum in the Netherlands. Tremors have been recorded at a magnitude of 3.4 on the Richter scale. The Times reporter explained that after more than fifty years of natural gas extraction in the area, recent earthquakes have become more common. Quoting from the Times article: Chief Seinen, a spokesman for the gas consortium known as NAM, said the extraction had created at least 1,800 faults in the region's subsoil. 'These faults are seen as a mechanism to induce earthquake.' he said. [8]
  • New Zealand: deliberate manmade earthquake at Christchurch, testing in 2012 [25]
  • Japan, 2011 Tohoku earthquake: time-dependent stress transfer and toggling effects of earthquakes [23]
  • Switzerland: geothermal projects
  • United States:
    • California: geothermal projects, mining projects (the 1992 Landers earthquake & the 1999Hector Mine earthquake) [17][22]
    • California: Simpson & Reasenberg reported on earthquake-induced static stress changes on central California fault lines [20]
    • Oklahoma: possible effects of oil well wastewater disposal into wells [27]
    • Oklahoma: possible effects of fracking *(hydraulic fracturing by injection of high pressure liquid into shale rock to obtain oil or gas)
    • Texas: use of water flooding to improve old oil well yield;

* The December 2013 New York Times article noted that fracking-related earthquakes occurred only over short time periods, unlike other earthquakes traced to or suspected as the cause of manmade earthquakes. [12]


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