Sichuan earthquakes can be caused by the ear

Some scientists are hypothesizing that an artificial dam could be the culprit that caused a massive earthquake in May last year in Sichuan province, China, killing 87,000 people and missing.

A flush of water at Zipingpu dam, Sichuan, China.Photo: cryptome.cn.

A geologist at Columbia University (USA), who has studied earthquakes for years, said the weight of 320 million tons of water in the Zipingpu dam caused a large fissure in the area to relax and cause seismic activity. . Many Chinese geologists also affirmed the huge pressure of water in the Zipingpu dam in Sichuan province to relax geological cracks, leading to disaster.

Fan Xiao, chief engineer of the Sichuan Geological and Mineral Administration, is one of the proponents of the hypothesis. 'The Zipingpu dam was built right on the area where the fracture caused the earthquake, so it was likely that it impacted on the crack,' he said.

In the scientific world, the phenomenon that Fan refers to is called the "seismic shock caused by a dam." In fact, dams in many parts of the world have caused earthquakes of varying degrees. But if Fan's assumption is correct, this will be the first time a dam triggers an earthquake of magnitude up to 8 Richter scale.

The Zipingpu dam has been in use since 2004, has a height of 156 meters and can hold up to 1.1 billion cubic meters of water. The building is located 5 km away from the epicenter. Fan said that since the end of 2004 to the end of 2005, Sichuan Geological and Mineral Administration recorded 730 earthquakes of less than 3 Richter magnitudes.

Fan added that the location of the dam is a very important factor. He discovered the terrible seismic phenomenon that happened at the right time when the water level in the dam was rapidly decreasing. 'For earthquakes caused by dams, the most dangerous phase occurs after the water level in the dam reaches its maximum and drops. That sudden change may cause the crack to become destabilized. Meanwhile, the water level in the Zipingpu dam dropped dramatically before the earthquake struck , 'he said.

Zipingpu dam looks from above.Photo: internationalrivers.org.

Lei Xinglin, a geological specialist at the China Earthquake Research Agency, also published a report last December, in which he confirmed the process of storing and discharging water in the Zipingpu dam affected the Geological fissures in the area of ​​earthquakes.

However, many other scientists in China rejected this hypothesis and claimed that the Sichuan earthquake was a natural disaster, not an ear. Wu Faquan, an expert at the China Institute of Geology and Geophysics, thinks that some natural forces underground cause seismic events.

'After many studies and surveys, most Chinese scientists concluded that the Sichuan earthquake was caused by the movements of the Earth's crust,' he said. The country's famous irrigation engineer Pan Jiazheng also rejected the human ear hypothesis and affirmed: 'Damming caused earthquakes with magnitude of up to 8 on the Richter scale is an unprecedented event in the world.'

So far, the world has only discovered four seismic tremors with magnitudes of 6 on the Richter scale caused by dams, one of which occurred in Guangdong province. But the chief engineer of Sichuan's Geological and Mineral Fan Office provided an additional proof that many areas had suffered from the shaking of the Earth's crust with lower intensity and the area around the Zipingpu Dam. once vibrated by a seismic with a magnitude of 6.5 Richter.

'Because the earthquake in the area is so strong, the Zipingpu dam can cause an earthquake of greater intensity , ' he explained. In Fan's view, earthquake prevention should be considered a top priority when repairing dams damaged by the Sichuan earthquake. He even called on the government to cancel a plan to rebuild some dams.

Many Chinese scientists believe that the link between dams and earthquakes has not been clearly demonstrated, so more research is needed to clarify.