Earthquake Potential in Central U.S. Now Similar to California - NBC Bay Area

Earthquake Potential in Central U.S. Now Similar to California

A quake forecast shows states in Central and Eastern United States now have the same chance of major damage from earthquakes as California does. And geologists know why: human activity.

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    NEWSLETTERS

    Induced Earthquakes Raise Chances of Damaging Tremors: USGS

    For the first time, the United States Geological Survey is releasing maps that show the potential ground-shaking hazards from human-induced quakes. In the past, maps from USGS only identified tectonic hazards. Raj Mathai reports. (Published Monday, March 28, 2016)

    Shaking, destruction and chaos are some of the dangers of living in California. But now other parts of the country are being told to brace for the same threat.

    A quake forecast shows states in Central and Eastern United States now have the same chance of major damage from earthquakes as California does. And geologists know why: human activity.

    “In a few states such as Texas and Oklahoma, Southern Kansas, the seismic hazard is comparable to many parts of California. Induced earthquakes – mostly from oil and gas activities – east of the Rocky Mountains has contributed significantly to the total seismic hazard,” U.S. Geological Survey geophysicist Arthur McGarr said.

    The USGS released one-year earthquake prediction maps taking into account both natural and human activities – the first of their kind — on Monday morning.

    The maps show ground-shaking risks nationwide, with the biggest upticks in regions with recent increases in oil and natural gas production. Specifically, waste water injection – that’s when oil companies re-inject salt water deep into the ground.

    “It’s mostly brine but sometimes contains some other chemicals that are considered fairly harmful,” McGarr said.

    Waste water injection, which stems from both conventional and enhanced production such as fracking and steam injection, can sometimes lubricate faults and cause earthquakes, according to geologists.

    In the Central and Eastern United States, the number of earthquakes has jumped more than 30 times in the last decade. Between 1983 and 2008, there was an average of 21 earthquakes of magnitude 3.0 and higher. From 2009 to 2013, the rate climbed to 99 earthquakes per year. And in 2014 alone, there were 659 earthquakes, according to the USGS.

    The agency says about 7.9 million people live in the vicinity of where these projected earthquakes could cause damage, mainly cracking in buildings. However, McGarr says the magnitude of a Central or Eastern United States quake could be up to a magnitude of 7.1, and if an earthquake of that size occurs near a city it could cause serious damage.

    “Where they might occur and how strong the ground will shake – and if that shaking translates into damage. And if it does, we need help people be aware of that damage so they can make more informed decisions,” said Mark Petersen, chief of the National Seismic Hazard Project.

    The issue with the maps is the limited data. USGS members said during a teleconference Monday that they need more data in order to squash any room for error. There is a lag with industry data, as oil companies are only required to release monthly numbers on injection volumes and pressures once a year.

    However, geologists say we are already three months into the 2016 projections and there have already been earthquakes in areas they predicted there would be.

    Back in the Bay Area, Geologists say human activity isn’t our biggest seismic threat. Instead, the natural threat from the Hayward Fault is.

    “It could be tomorrow,” McGarr said of an earthquake occurring along the Hayward Fault, which could be about a magnitude 6.7. “In a sense, it’s overdue.”

    Geologists say there is so much naturally occurring seismic activity in California that they were not able to distinguish manmade earthquakes from natural ones in the projection maps released today. However, they will be investigating a handful of areas with human activities such as the Coso region, Salton Trough, Los Angeles Basin, and The Geysers.

    The Geysers are north of San Francisco and have geothermal activities such as steam injection to extract oil from the ground.

    McGarr says other “at risk” states may look towards California as a state to model changes to emergency response and building codes. However, earthquakes in the Central and Eastern U.S. are more like “pulses,” as opposed to California’s “ruptures.”

    The USGS hopes to release new earthquake outlooks annually to keep up with the changing oil production and earthquake risk. Previously, the agency released projections every 50 years.

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