Humanity little is known about the structure of the earth.It is no longer possible to control many of its internal processes.Among such phenomena include earthquakes that cover a certain area of the earth's surface and in seconds turn it into rubble.
major earthquakes in California
One of the largest earthquakes occurred in California (USA).Such has not happened for about 25 years.The area has been subject to fluctuations in the 6 points.It happened in 08/24/2014 03.20 am local time.It was at this time the inhabitants of San Francisco felt the first tremors.
Despite the considerable damage among the buildings and communications, managed to avoid casualties.Although about 80 people still suffer.
thereby avoiding many of the victims?
Many believe that the number of victims is relatively small because of the special security system that was created as an experiment in California.Its essence warnings of possible disasters.Earthquake in California (2014) showed that the system works.She reported on the push coming in 10 seconds.
known publication The Los Angeles Times wrote about this, that "for those few seconds, you can all but drop out of bed."In many ways they are right, but the work is hard to provide such a system all residents of the state and modify it so that the warning signal received for 50 seconds before the disaster.
system works with the help of seismographs, which record tremors in the epicenter.They are able to feel the push and the first to send a signal to the people with the speed with which it comes before the quake.Thus, people will be able to prepare for disaster.
earthquake in California has shown once again the fragility of human structures.Although optimism adds a warning system has been activated.Of course, 10 seconds is not enough for the evacuation, but progress does not stand still.In the future, even 50 seconds can save many lives.
earthquake in California was not the only one in the history of the region and the United States as a whole.In recent years, this state has ceased to be a leader in the number of aftershocks.
Oklahoma - the new leader in the number of disasters in the United States
Most residents of this state until 2008, had no idea that an earthquake in the United States.They were far from these problems.However, in recent years in the area recorded 240 aftershocks of magnitude up to 4 points.
Most experts agree that it is connected with the extraction of shale gas.This opinion is shared professor at Columbia University, Jeffrey Abers.He states that the risk is approximately 2,000 km² of Oklahoma.State a few years has become the most earthquake-prone US location.
main reason is called shale gas method of hydraulic fracturing.It lies in the fact that a small amount of water and chemicals at high pressure is injected into the oil shale formations.Thus, fossil fuel is released.As proved by scientists at Cornell University, that such action could cause an earthquake in the US and other countries within a radius of 40 km from the mining operations.
Municipalities of many cities in the United States prohibit the extraction of oil and gas companies to produce by this method.In this country, in addition to man-made disasters, and so there is something to fear and what to remember.
when America was shaking the longest?
earthquake in California in 2014 was not the greatest in the history of the region.Much earlier, in December 1811, it started a movement of the earth, which ceased only in March 1812.As a result, a wave of tremors have been many changes in the terrain.
consequences of the earthquake:
- individual plots up to 6 m in height;
- changed over the Mississippi River;
- , new lakes, such as St. Francis;
- killed large numbers of people.
Scientists suggest that 3 to 5 aftershocks were of magnitude more than 8 points.The exact number of victims will never be known, because the settlements has been no rigorous documentation.
greatest cataclysm in San Francisco
Earthquake in America in 1906 was much shorter.It happened on April 18 and lasted only 75 seconds, but it brought a lot of human lives and destruction.
- deceased considered more than 700 people.
- were destroyed as new buildings, such as the municipality and dilapidated houses.
- Sonoma Wine Company was ruined due to the complete destruction of your wine store.
- As a result, fire broke out were burned about 12 square kilometers.Many insurance companies paid compensation for damage suffered as a result went bankrupt.
- completely destroyed the city water tank and gas storage.
propulsion power is estimated at 8.3 points.This has damaged the city in 500 million dollars.Hundreds of lives claimed this earthquake.
strongest earthquakes in history
hardly an earthquake in California could be compared with what happened in August 1950 in India.It happened in the east of the country, in the state of Assam.The tremors were so strong that special equipment was not able to fix them.Sensors were not designed for such indicators.
When everything stopped, experts officially assigned shock force of magnitude 9 points.Cataclysm has brought huge losses and destruction.There were casualties.It lasted five days.As a result of prolonged shocks formed more and more faults, people instantly lost not only homes but also their lives.From slots formed out of thick hot steam.
damage from the largest earthquake in the world amounted to $ 25 million.In addition to the human toll, the worst was the complete destruction of infrastructure.They were destroyed by dams, dikes and roads.All this has led to a lot of other problems, including complicated the search and rescue of survivors.
Many residents had no choice but to escape to the trees.Newspapers have described many such cases.Features highlight one of them, when a woman had to give birth in a tree.
Where is shaking, really?
waves of aftershocks August 15 reached America.US recorded their equipment at home.The researchers suggested that they come from the Japanese islands.They, in turn, also recorded similar figures and decided that the cataclysm has covered the United States.
None of them had not even thought at first that these waves are echoes of the earthquake in India.His power has spread to a large part of the Earth.
India has long been an unstable position of the crust.That is why there earthquakes and floods.In the second half of the 19th century in India have already occurred such cataclysms of magnitude higher than 8 points.
Why do earthquakes occur?
order to calculate in advance the places where tremors will occur, and avoid a lot of casualties, it is necessary to understand why they occur.Scientists are not fully aware of how and why there are many disasters.Regarding earth tremors there are several versions.
main causes of earthquakes:
- failures in the ceiling formed underground cavities.These shocks have a small area of coverage, but cause a lot of serious damage.For similar reasons can be attributed to human activity, namely vykachku oil and gas out of the ground.
- Volcanic eruptions often accompanied by severe earthquakes.It is associated with a sudden rarefied gas that accumulates in the channel of the volcano.After the eruption of lava can also be formed already mentioned void.
- tectonic earthquakes in the world are considered to be the most destructive.They are associated with moving platforms and fractures in granitic formations of the earth's crust.An example is the scene in California.All of them are associated with fault San Anderas.It is regularly formed along a seismic wave which, depending on the speed, bring more or less extensive damage to this state.
possible to predict a cataclysm?
Ability to make the correct prediction of earthquakes is the main task of scientists and seismologists.Thousands of stations operating around the globe following the internal motion of the earth, which never stops.
often used to predict the knowledge that an earthquake is a cascade of proliferation cracks in the earth's crust.They occur in places faults.That is why the observations and measurements are carried out on a seismically dangerous areas.Termination of the internal processes of the Earth - is a high probability that an earthquake will happen soon.
Scientists create a special card, which displays information about the outbreaks of aftershocks, their intensity, frequency.Forecasting is carried out in three stages.
throughout the forecasting process:
- Detection of seismically dangerous areas for 10-15 years.
- Medium-Term 1-5 years.
- Short-term forecasting when a high probability of disaster in the area.
What causes erroneous forecast?
well studied causes of earthquakes, the scientists manage to make predictions - to predict them.The most impressive was forecast in China in 1975.The city was alerted at 14.00 universal anxiety and tremors began at 19.36.Despite the complete destruction of the village, there was virtually no casualties.Magnitude reached 7 points.
However, the case for scientists and failures that result in serious economic losses.This is due to the fact that, in addition to the evacuation, it is necessary to stop the operation of industrial enterprises, disable all energy sources.
main task of seismic forecasting disasters is not solved.However, work on this problem conducted by bringing the results.