Scientists Jiemi frequent reason for this earthquake: crustal deformation caused by groundwater
Since 2010, some of the world seems to frequent earthquakes: from Haiti, Chile, Turkey, Japan, Mexico to Indonesia earthquake, magnitude are more than seven. Global seismic activity unusual yet? Experts say “high earthquake of that” controversy exists.
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April 11, in the Solomon Islands this year, more than magnitude 7 earthquake in the second. Since 2010, some of the world seems to frequent earthquakes: from Haiti, Chile, Turkey, Japan, Mexico to Indonesia earthquake, magnitude are more than seven. Global seismic activity unusual yet? Does this mean – According to statistics, this year more than the global level 6 earthquake would have been more than 10 times. Seismic gap in the large magnitude earthquake is smaller after another, from the information available to the China Earthquake, April 6 have occurred in the world for more than 4 earthquake.
According to the U.S. Geological Survey provides the data 134 times the world average in each of the magnitude 6 to 6.9 earthquake, 18 from magnitude 7 and 7 earthquakes. However, so far this year have occurred in the earthquake of similar magnitude over the most years of the same figure. Online People joke, and now the Earth has been as mobile as he was transferred to a “vibration mode.” Well, now it has entered the world of high earthquake? Earthquake experts have different views on this.
“Period of high seismic say” there is controversy
High-fat, said China Earthquake Networks Center research fellow Shih-Hung Sun that now the world may be in a time of frequent earthquake activity. He said the comparison with the past one hundred years the history of seismic activity in 1964 and 2004, it did not happen 40 years more than 8.5 earthquakes have occurred twice this year, more than magnitude 8.7 earthquake, which is more than 40 years of relatively low level of activity The state took place, indicating that more than eight years of global seismic activity level was high, and the first half of last century, almost equal to the level of seismic activity. The first half of last century when a higher level of seismic activity, is relatively weak when the latter half of the 21st century there are increased signs of seismic activity. “If there is a hundred years seismic activity period features, it may now and again into the high-magnitude earthquakes frequent stage.” He believes that the era of high seismic activity may continue for some time, estimated that at least 40 years.
Normal that the “single from the data point of view, does intensive earthquake in recent years, indicating a relatively strong earth movement, but not that the earthquake has entered a period of frequent earthquakes, earth science theories and observations so far not been can give a clear conclusion. “Earth and Space Sciences, Peking University, Associate Professor Dr. Lei Jun said that this year’s seismic activity is normal area, and eight more earthquakes occur, indicating that a very large seismic energy release has been released. Future earthquakes will continue for quite some time, but in time may be elongated, although the magnitude will be maintained at a certain intensity, but will be alleviated.
Institute of Geology, China Seismological Bureau, said researcher Jian-Dong Xu, global earthquake is still in the normal level, and now all over the world more and more advanced communication system, people can learn more about the news of the earthquake. China Seismological Bureau requested the domestic four earthquakes have been announced, making reports increased the public feeling more and more frequent earthquakes.
Circum-Pacific seismic belt most active
Institute of Geophysics, China Seismological Bureau, said Dr. Chen Bin, the world’s three major seismic zone, are circum-Pacific seismic belt, the Eurasian seismic zone and the ocean ridge seismic belt. According to available statistics, the circum-Pacific seismic belt is the world’s most widely distributed, the largest earthquake in the earthquake zone, the energy released more than 80% cent of the world, in other words, about 90% of the world’s earthquakes occur in the circum-Pacific seismic band, while seven or more than 80% of earthquakes occurred in this region, the global outbreak of more than magnitude 7 earthquakes have also occurred in most Pacific seismic belt.
Why Pacific seismic belt of frequent earthquakes? According to theory of plate movement, the world is divided into several sections, the middle of the Pacific plate rapid expansion of mid-ocean ridges, so what both sides of the plate edge and plate and the Americas, Asia-Europe plate collision, causing frequent seismic Pacific region. That the earthquake was not evenly distributed in the earth, but rather focus on the plate boundary zone. In general, the internal plate, the crust is relatively stable, while the junction plate and the plate is the crust more activity areas, where volcanic and seismic activity and fracture, extrusion fold, rising magma, crustal subduction and so frequent. The Pacific plate boundary in the plate is the most active, so earthquakes and volcanism are the most frequent.
Scientists have discovered new causes of earthquakes – water
In general, the production includes three causes of earthquakes:
Tectonic origin: This earthquake is also known as fault earthquake, the rock from the ground caused by a sudden dislocation, this type of earthquake most widely distributed, its intensity is the highest, about 90% of the earth and the most destructive earthquake earthquakes are fault earthquake;
Volcanoes: volcanic eruptions that time because of the impact of gas caused by the earthquake, the earthquake intensity of this small area around the volcano is more significant impact, the total number of volcanic earthquakes accounted for 7% of the earthquake;
Fall Cause: In the limestone areas of development, a huge rock formation is underground dissolution cavity, or exploitation of mineral resources, the formation of mined areas, the earthquake caused the collapse of overlying strata, the scope of this earthquake is small, less destructive, accounting for the total number of earthquakes 3%.
Published in the recent “Nature” magazine on the study expands our understanding of the causes of earthquakes. University of Utah Institute of Energy and Earth Sciences geophysicist using a known method of magnetotelluric sounding (similar to CT scanning the patient using X-rays), on the South Pacific on the Pacific Plate and the Australian plate the subduction zone research and found the water on the earthquake generated an important role. New Zealand South Island’s east coast following the Pacific plate began to sneak into the Australian plate under the ground about 10 miles, hydrated minerals in the water contained is released, most of the water to rise over the Australian plate crust, further damage rock, expanding cracks. This grid-like structure of the fault rupture undermine the stability of the crust, and promote new formation of strike-slip faults. Here, the past 200 years, there had been close to eight major earthquake, these earthquakes are all with the strike-slip fault. The role of fluids makes the crustal deformation and earthquake generation to create the conditions.