In Braxton [WV], there's a whole lotta shakin' going on

"After four quakes rattled the county in April, followed by two more in May, Given received a letter to the editor from Marshall University geology professor Ronald Martino in June, addressing the topic of local earthquakes.

"I realize there has been some anxiety over the recent earthquakes in Braxton County," he wrote. "It is quite possible that these earthquakes are the result of fluid injection. Drilling in the Marcellus Shale for natural gas in Northern West Virginia has involved hydrofracking of horizontal wells, which has produced large amounts of wastewater. The disposal of this water, as well as brine that is produced from oil and gas wells, is injected back into the earth at a depth of up to several thousand feet."

Martino added that geologists have known for a half-century that "fluid injection along locked faults can trigger small to moderate earthquakes." The increase in fluid pressure, he wrote, essentially lubricated "the frictional resistance to movement along the fault zone, allowing the fault to slip more readily." ..."

http://sundaygazettemail.com/News/201008280386

This doesn't really apply here, just thought it was interesting

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Replies to This Discussion

Permalink Reply by William Ladd on August 29, 2010 at 8:55am
Isn't it better to have many small earthquakes the to have one hellish shake like they have in california? Smaller ones reduce the pressure building up so high that when they do break loose damage is not so great!

Bill L.
aka Bummy
Permalink Reply by Ann Ticopa on August 29, 2010 at 12:54pm
It doesn't seem to work that way. There is the risk of triggering the maximum potential earthquake for an area. There is a geothermal area in northern CA known as The Geysers where they have been drilling down and tapping steam for years. But there was a newer project (AltaRock) where they drill further down into non water bearing rock and hydrofrac. The company appears to have abandoned the project in Dec., 2009.

"How Does Geothermal Drilling Trigger Earthquakes?

Do these little earthquakes help relieve any building pressure to help stave off larger quakes?
Unfortunately that's a myth.

Does deeper drilling mean stronger earthquakes?
The more important issue is how big a fracture is—how big an earthquake are they generating. If they intersect an existing fracture, and it's ready to go, they can trigger a bigger earthquake. ..."

http://www.scientificamerican.com/article.cfm?id=geothermal-drillin...
Permalink Reply by William Ladd on August 30, 2010 at 1:32am
What you say may be true. But it seems to me that if pressure for a quake is building up, then when it finally does let go the quake would be much larger and more destructive.

For example if you blow a balloon up only part way and poke a pin in it, the explosion will not be anywhere near what it would be if you blew that balloon up to the maximum size.

Or take a tire and pump air into it. The higher the pressure you force into it, the more damage it will do when it finally blows.

An earthquake might be triggered to cut loose much earlier by fracting in the area then it otherwise would.

Bill L.
aka Bummy
Permalink Reply by Ann Ticopa on August 30, 2010 at 3:16am
It's not what I say, it's what "U.S. Geological Survey Earthquake Hazards Team seismologist David Oppenheimer, who is based in Menlo Park, Calif., just a couple hours south of the area." says.

The concern is that a man-caused smaller earthquake on/near a fault might trigger a larger one in the existing fault. A geothermal project in Basel, Switzerland was shut down after it caused some small earthquakes. In a densly populated area, even small earthquakes can (and did) cause millions of dollars in damages. And there was an estimated 15% chance the project could trigger a half-billion dollar earthquake.

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