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The number of large earthquakes, which may be on the rise, has doubled for the first part of 2014 compared to that, which occurred in 1979 according to a report written by Becky Oskin of CBS News. Oskin reported on a study that compared the rate of earthquakes measuring 7.0 in magnitude or greater with those that occurred back in 1979. According to her report, a 65 percent increase in larger earthquakes has happened since then. Oskin stated the rate of large earthquakes in 1979 was 10 per year, in 1992, it was 12.5 and in 2010, the number climbed to 16.7 per year.
Oskin stated the rising rate in the first three months of 2014 “more than double the average since 1979.” According to a study published on June 21 by Geophysical Research Letters, lead author and geophysicist of the U.S. Geological Survey, Tom Parsons, said Planet Earth has experienced some of the highest rates of significant earthquakes recorded, and the global rate is on the rise. Parsons added the phenomenon can still only be explained by “random chance,” and that large-scale earthquakes do not seem to trigger other large-scale earthquakes, but that smaller magnitude earthquakes, such as those measuring 5.6 or less do cluster together and may even influence one another.
Large earthquakes may be on the rise, but one type of deadly earthquake that, luckily, does not occur frequently is known as tsunami earthquakes. According to Kelly Dickerson of Fox News, scientists first discovered these types of earthquakes 35 years ago, but since tsunami earthquakes rarely happen, scientists cannot study them often.
Dickerson referred to a journal published on May 5 called Earth and Planetary Science Letters that reported on tsunami earthquakes that happen when two sections of Earth’s tectonic plates become “hung up on extinct volcanoes on the ocean floor.” Researchers refer to these as “sea mounts” that get squashed in subduction zones where two tectonic plates collide, and one slides beneath the other. Researchers believe this kind of earthquake may have taken place in 1947 in New Zealand, triggering two tsunamis that may have reached 43 feet. Researchers further clarified saying these kinds of ruptures can cause slow-moving tsunamis, which differ from those generated by large earthquakes that are “two to three times faster.” Researchers believe tsunami earthquakes may have occurred in nine other instances, including in Nicaragua after a 1992 earthquake hit the area measuring 7.2 on the Richter scale and in 2006 off the coast of Indonesia.
Researchers also reported an account of eyewitness testimony, tsunami earthquakes tend to have more of a rolling feeling, and according to lead researcher Rebecca Bell, may “shake the ground gently for a long period of time,” thereby causing a tsunami. In that case, residents living close to a subduction zone or near any coast should adhere to any warnings if this kind of “prolonged” and “gentle” shaking is felt.
Although large earthquakes are on the rise, and tsunami earthquakes can happen near the coast, other types of unusual earthquakes are taking place in Oklahoma. About 230 earthquakes measuring 3.0 or greater have been reported so far this year alone. Kevin Schultz of Scientific American stated that in 2008, Oklahoma averaged only one earthquake a year, so the surge in movement has left residents and scientists baffled about the cause.
Schultz reported that past research has attributed seismic activity to “wastewater injection” at oil drilling sites, and that of “fracking.” According to Schultz, a recent study published in Science revealed this attribution to be even truer as scientists created a model using the flow of water and calculated the physical properties of “impermeable layers of rocks” similar to those that have been injected with wastewater. This kind of method has been used since the 1960s to rid “millions of barrels of wastewater” in what was known as “a disposal well.” Researchers concluded fluid pressure underground “reduces the frictional strength of faults” and have allowed faults to slip, which can be felt as far as 20 miles away.
Earthquakes may be on the rise in Oklahoma. Co-author of the study, Geoffrey Abers with Cornell University reported the amount of wastewater injected into disposal wells doubled between 2004 and 2008 for the production of oil and gas, with injections occurring in Oklahoma, Texas and other states as recent as this past year. Large earthquakes may be on the rise, but unusual earthquakes in the U.S. may possibly be prevented by simply halting the method of wastewater injection.
By Liz Pimentel