2009年起，美國中部和東部出現多起人為活動引起的地震。美國地質調查局（USGS）認為，這乃是油氣業將廢水或其他液體注入深井所致。
美證實：開採石油「誘發地震」
USGS科學家發現，美國8州共17處的「誘發地震」活動率增加。誘發地震指的是人類活動改變地殼壓力和張力所導致的地震。
1973至2008年間，美國中部和東部平均每年僅出現21次規模大於3的地震。2009年至2013年暴增至美年99次規模3以上地震，活動率還持續升高。2014年總共發生659次規模3以上地震，大多介於3到4之間，雖有感但不致造成太大損失。部分州也曾出現規模5以上地震。
USGS首次針對這些誘發地震的危險性發表綜合報告。頻繁出現誘發地震的州有阿拉巴馬州、阿肯色州、科羅拉多州、堪薩斯州、新墨西哥州、俄亥俄州、奧克拉荷馬州和德州。目前發生次數最多的屬堪薩斯州和奧克拉荷馬州。
廢水處置增加孔隙壓力
石油和天然氣生產過程會產生大量的廢水。這些高鹽份、化學物質污染的廢水，將注入特別建造並經過核可的深井中，以防污染淡水水源，但這同時會增加地下孔隙壓力。
USGS報告指出，孔隙壓力增加可能導致附近斷層滑動，增加地震發生機會。但報告也指出，雖然廢水注入深井的作法可能引發地震，大多數深井不會引發有感地震。
有人懷疑水力壓裂可能引發地震，但USGS認為，裂解過程並非有感地震的主因。
USGS分析誘發地震常見地區的地震活動率、地點、最大規模和地動方式，開發出可預測深井附近或其他誘發地震增加的工業作業地區地震的電腦模型，計算出接下來12個月的發生頻率和震度。
報告中分析的17個地區，地震活動性增加的規律皆不盡相同。有些地區地震活動間歇性的發生，如德州科格德爾和科羅拉多州蘭芝利。有些地區地震活動率呈現指數增加，持續至2015年。
The number of earthquakes triggered by human activities has soared since 2009 in the central and eastern United States. New research by the U.S. Geological Survey links the increase to industrial operations that dispose of wastewater or other fluids by injecting it into deep wells.
USGS scientists identified 17 areas in eight states with increased rates of “induced seismicity,” which means earthquakes and tremors caused by human activity that alters the stresses and strains on the Earth’s crust.
Between the years 1973–2008, there was an average of 21 earthquakes of magnitude three and larger in the central and eastern United States. This rate jumped to an average of 99 M3+ earthquakes per year in 2009–2013, and the rate continues to rise. In 2014, alone, there were 659 M3 and larger earthquakes . Most of these earthquakes are in the magnitude 3–4 range, large enough to have been felt by many people, yet small enough to rarely cause damage. There were reports of damage from some of the larger events, including the M5.6 Prague, Oklahoma earthquake and the M5.3 Trinidad, Colorado earthquake.
This report is the first comprehensive assessment of the hazard levels associated with induced earthquakes in the United States. These human-caused earthquakes are occurring in eight states: Alabama, Arkansas, Colorado, Kansas, New Mexico, Ohio, Oklahoma, and Texas.
The greatest number of induced earthquakes by far have been felt in Kansas and Oklahoma.
Large volumes of polluted wastewater can result from energy production, among other industrial processes. Wastewater that is salty or polluted by chemicals needs to be disposed of in a way that prevents contaminating freshwater sources. Deep well injection of wastewater increases the underground pore pressure.
The USGS report states that increased pore pressure may “lubricate nearby faults thereby making earthquakes more likely to occur.”
Although the wastewater disposal process has the potential to trigger earthquakes, most wastewater disposal wells “do not produce felt earthquakes,” the report states.
Questions have been raised about whether hydraulic fracturing, known as fracking, is responsible for the recent increase of earthquakes.
USGS studies suggest that “the actual hydraulic fracturing process is only occasionally the direct cause of felt earthquakes.”
The USGS report outlines a preliminary set of computer models to forecast how hazardous ground shaking could be in the areas where sharp increases in seismicity have been recorded located near deep fluid injection wells or other industrial activities capable of inducing earthquakes.”
The models aim to calculate how often earthquakes are expected to occur over the next 12 months and how hard the ground will likely shake as a result.
Scientists developed the models by analyzing earthquakes in these zones and considering their rates, locations, maximum magnitude, and ground motions.
Patterns of increased seismicity vary between the 17 different areas analyzed in the report. Some areas show pulses of increased activity interspersed between periods with little or no activity as in Cogdell, Texas, and Rangely, Colorado.
Other areas, such as central Oklahoma and southern Kansas, show exponential growth patterns of seismicity that are continuing in 2015.
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