Sixteen major tectonic plates of the planet is in motion. The fact that they do not stand still, we are reminded of the earthquake, which resulted in the last 7 years have killed more than half a million people. The most devastating were shaking the ground in Southeast Asia in 2004, Haiti in 2010 and in Japan in early March.
Where is the next can occur a powerful burst of energy to the surface of the Earth's crust? One of the most unstable places tectonic scientists believe the San Andreas Fault on the West Coast of the USA. And some people even believe that the disaster may prove fatal for California …
Pacific Coast of North America — one of the most active seismic zones of the world. Here there are two large lithospheric plates — the Pacific and the North American, the boundaries of which are breaks the crust. San Andreas Fault — one of the boundaries between the two plates. It stretches for 1,300 km from southwest to northeast, diagonally across California. Its average depth is 16 km. For the last 3 million years, the average rate of plates along the fault was 5.6 cm per year. About as fast growing nails in humans.
The Pacific plate is moving to the north-west, North American — in the south-east. When traveling, they are constantly in contact, which ultimately is the cause of earthquakes. Deep under the ground slab stumble on ledges of solid rock, thus closing on each other. Longer holds "castle", the more splash of energy to the Earth's surface.
California remember …
The city of San Francisco, standing almost on the edge of the San Andreas Fault, already had a similar output accumulated energy. It is here April 18, 1906 earthquake, the power of which, according to various estimates, 7,8-8,3 on the Richter scale. At the beginning of XX century, there was no concept of earthquake-resistant building. Therefore, San Francisco was almost completely destroyed. Because of the explosion of gas communications city was engulfed in flames. Wooden houses flashed as matches. Then killed about 3,000 people, no less than 225 thousand homeless. Break the crust can be observed for 470 km. Depth of some cracks was 1 meter and width — 6.4 meters.
Once again, the San Andreas made a name for himself April 17, 1989. The epicenter of the earthquake was located 10 km from the mountain top of Loma Prieta. Fortunately, at that time, many of the buildings have been constructed with the increased seismic activity in the region. However, 62 people were killed and more than three thousand were injured. At least 18 thousand homes were destroyed — mostly in the city of Santa Cruz, where many old buildings preserved late XIX — early XX century.
Two examples — the most famous and dramatic in terms of human losses and destruction. However, in the history of the State of California are not the only ones. Earth "Golden State" goes shaking an average of 30 times a day. Only in the last two weeks, the U.S. Geological Survey (USGS) has recorded more than 10 aftershocks ranging from 3 to 3.5 points, not to mention the weaker vibrations. In theory this is a good thing, because these little shake to prevent the accumulation of excessive power budget. But …
Calm before the storm
The fact is that apart from the "great and terrible" San Andreas is located nearby many minor faults and fractures. At least five large enough. Tremors occurred mainly in these cracks and fractures. In the same San Andreas Fault intense seismic activity was observed only in the northern part. While its central segment of the last major earthquake in 1857-m, that is more than 150 years ago.
The more time passes since the last tangible tectonic shift, the greater the chance of a powerful earthquake in the future. In this regard, of particular concern is the southern segment of the San Andreas, which for 300 years in a state of suspicious silence. Fears grow given the fact that this area is densely populated cities such as Riverside, Long Beach and Los Angeles. For scientists, one thing is clear: a major earthquake in California is inevitable. It is only a matter of time.
The most authoritative forecast UCERF was prepared by a team of scientists and experts from the United States. The most likely place rouse — Southern California, this is where the last three hundred years reigns calm anxiety. According to the forecast UCERF, earthquake M? 6.7 occurs with a probability of 99.7% over the next 30 years. This study also gives 46% in favor of a possible earthquake size M? 7.5 during the same time period. However, the study was carried out four years ago. During this time the conditions have changed and variables that had an impact on the final result.
The Russian center of earthquake prediction "Geokveyk" suggests that Americans are wrong. Instead offered a mysterious method of seismic entropy, which produced disappointing findings for Americans. A high-risk, as in the previous forecast, was Southern California. Here are just a "Geokveyk" believe that an earthquake M? 7.5 to happen before 2016. This does not prevent that disaster can happen north of Los Angeles in 2011.
Yuri Fialko, professor at the Institute of Oceanography Skrippa, and colleagues tried to assess the impact of a possible seismic gap, again in Southern California. The basis was taken 7,8 degree earthquake with its epicenter in Bombay Beach. According to calculations Fialko, shaking the earth can take about a minute. With such power and duration even earthquake-resistant buildings can simply not sustain the load and collapse. The most conservative estimate of Mr. Fialko, in case of aftershocks of at least 1,800 people die and tens of thousands are injured. The economic damage will be at least $ 200 billion in tips professor at the Institute of Oceanography Skrippa encourages all residents to get a basic State plan in case of emergencies. Need to have fire extinguishers and means to provide first aid. It is also important to have a supply of drinking water, which will last at least a few days.?