Elucidation of the mechanism of earthquake induced by human hand

ByPROColin Crowley

Since 2009, the occurrence of earthquakes has been rapidly increasing in the eastern and central parts of the United States, many of which are related to the extraction of crude oil, gas and geothermal energy that send a large amount of water to the rock, the United States The Geological Survey shows the relevance of energy mining and earthquakesPublish reportI have done it. At the time of publication of the report, the details of the mechanism to send the water to the rock by the mining and the mechanism of the earthquake occurrence were not scientifically shown, but the joint research team of California Institute of Technology, USA, France, I made it clear for the first time.

Supporting Online Material for - Guglielmi-SM.pdf

Seismicity triggered by fluid injection - induced aseismic slip - Caltech AUTHORS

The surface layer of the earth is made of a hard rock called a plate, and it touches the boundary where the plates are pushing each otherstressIs locally enhanced and an earthquake occurs due to the occurrence of a fault. This is a generally known earthquake mechanism, but this time it is about the induced earthquake that is said to occur due to anthropogenic causes.

In the US there is a huge fault that lasts about 1,300 km from the southern part of California to the west, the San Andreas fault, but at the same time there are also many small faults branching from the huge fault. The research team conducted an experiment in which a large hole was made on a fault of about 1.6 km or more and liquid was injected into the hole. First of all, we opened a hole of roughly 280 m in the rock, and we launched a machine called SIMFIP equipped with sensors measuring pressure, water discharge rate, rock motion and so on. After that, about 1 ton of water was injected using pressure, and the data recorded by SIMFIP was analyzed.

ByMichael R Perry

According to the analyzed data, it was not long since water was injected, and basement bedrock started to slide slowly. However, this type of movement is called "non-earthquake slip" and it is said that there is no direct relation with earthquake occurrence. However, due to non-seismic slip, the rocks on the front and back of the bedrock are separated, causing a phenomenon in which the amount of water flowing through the bedrock increases drastically. Eighteen minutes after injecting water, the occurrence rate of non-earthquake slip increased and seismic waves occurred from the rock, resulting in magnitude 1 to less than 3Micro earthquakeOccurred in large quantities.

Experiments show that the injection of a large amount of water into the rock does not directly generate a micro earthquake, but non-seismic slippage caused by a large amount of water increases the stress on the rock causing an earthquake It turned out that it was.

Emily Brodsky, a seismologist at the University of California at Santa Cruz, who is not participating in the experiment, said, "In a study by a joint team of the California Institute of Technology and the US, France, the experiment is close to the mechanism of the earthquake, I grasp the statue at an unprecedented level ". In addition, the results of this research are valuable data that never gotten to companies that are mining crude oil, natural gas and geothermal energy, and it is hoped that mining plans based on this data will be obtained.

Regarding the earthquake, the US Geological Survey Institute measures and counts earthquake shaking from acceleration sensors mounted on many smartphones, instantaneously locates the epicenter based on smartphone position, shaking intensity and direction, and reports it "EEW"Stanford University uses low-cost strong earthquake observation network using sensors attached to PCs around the world"QCNIn Mexico it is possible to issue an alarm 60 to 90 seconds before the earthquake arrivesEarthquake early warning systemThe development of new technologies to prevent large damage by early discovery in various fields such as development has been advanced and expectation for further progress in the future will be taken.

in Science, Posted by darkhorse_log