An eathquake on Nov. 5, 2011 caused extensive damage to the towers (turrets) atop Benedictine Hall, the most prominent structure on the campus of St. Gregory's University in Shawnee.
JIM BECKEL/NewsOK.com
By WAYNE GREENE World Senior Writer
Published: 12/6/2012 2:53 PM
Last Modified: 12/6/2012 2:56 PM
Whether a 5.7-magnitude earthquake that shook the state in 2011 — the biggest in contemporary state history — was man-made or not is still an open question, state geology experts say, and regulators say so is the issue of whether they should do anything about it.
The Nov. 5, 2011, earthquake near Prague — which was felt widely across the state — was “likely triggered” by fluid injection in the area, according to a paper presented by University of Oklahoma seismologist Katie Keranen on Wednesday at the fall meeting of the American Geophysical Union in San Francisco.
But Oklahoma Geological Survey officials say there’s a significant and important distance between likely and certainly.
In fact, there may never be enough evidence to make a definitive finding about what caused the Prague earthquake, said Austin Holland, research seismologist for the Oklahoma Geological Survey, in a telephone interview from the San Francisco conference....
How convenient, there may never be enough evidence to make a definitive finding. So, does that mean the USA should allow this destructive industry continue to cause seismic activity when there is so much more evidence elsewhere in the country to back this up?
There were recent findings in Texas to the destructive power of hydraulic fracturing from four separate sites where less than 2 on the Richter Scale was measured.
I have repeatedly stated the greatest danger to the USA through seismic activity due to the petroleum industry is liquefaction. Now, if everyone wants to continue to play around with this disaster they can look forward to loss of land use. I sincerely would not recommend it. This is the dynamic that has Christchurch, New Zealand in shambles.
I am fairly sure if geologists were commissioned to examine any seismic site believed to be caused by hydraulic fracturing and/or known to be cause by hydraulic fracturing in the USA, there would be some evidence of liquefaction. Fairly sure of that.
The scientists in the USA have been concentrating on proving the seismic activity is related to hydraulic fracturing, so they might not be focusing on the land condition left in its wake.
Liquid is introduced during hydraulic fracturing. It would enhance the ability of the ground to become loose during the seismic activity.
In geology, liquefaction refers to the process by which saturated, unconsolidated sediments, primarily sands and silts, temporarily lose strength and behave as a viscous liquid rather than as a solid. Ground failure caused by liquefaction is a major cause of earthquake damage and casualties. Photo source: Saitama Shimbun/Associated Press/Kyodo News
The scale of Japan’s March 11 earthquake and tsunami wasn’t the only thing that surprised geologists.
The 9.0 earthquake in Japan, the fourth most powerful quake ever recorded, also caused an unusually severe and widespread shift in soil through liquefaction, a new study suggests.
Near coastlines, harbors and rivers, earthquakes can make the wet, sandy soil jiggle, turning it temporarily from a solid to a liquid state, a process known as liquefaction. Heavy sand and rock sinks, while water and lighter sand bubble to the surface. The slurry spreads, often toward the water, and the surface shifts.
Japan’s liquefaction occurred over hundreds of miles, surprising even experienced engineers who are accustomed to seeing disaster sites, including from the recent earthquakes in Chile and New Zealand.
The study raises questions about whether existing building codes in other vulnerable locations can enable structures to withstand massive liquefaction, including in areas of Oregon, Washington and California.
“We’ve seen localized examples of soil liquefaction as extreme as this before, but the distance and extent of damage in Japan were unusually severe,” said Scott Ashford, a study team member from Oregon State University....
