California earthquakes
California earthquakes are developing by the movement of huge blocks of the earth's crust; Pacific Plate and North American Plate. The Pacific Plate is moving northwest, breaking horizontally past the North American plate at a rate of about 2 inches per year. About two-thirds of this movement occurs with the San Andreas error and some other parallel errors. Over time, these faults produce about half of the significant earthquakes in the region, as well as many minor earthquakes.
California Earthquake Prediction
Earthquakes occur suddenly, without warning, at any time of the year and at any time of the day or night. Sponsored by the US Geological Survey (USGS), the California Geological Survey (CGS) and the Southern California Earthquake Center (SCEC); The 2007 California Earthquake Probability Working Group released California's Unified Weather Forecast (UCRF). It says that in California, the probability of 99.7% has a moment Mw = 6.7 earthquake (the same as the Northridge event) over the next 30 years. The southern segment of San Andreas guilt has the highest probability of creating such an earthquake scenario in southern California with a 67% chance of hitting a large area of Los Angeles, while Hayward's error is the most likely source of earthquakes in northern California with a probability of 63% hitting the area of San Jose Francisco. Larger earthquakes are less likely during the same time period; 94% probability of an event Mw = 7.0, probability of error Mw = 7.5%, probability of an event Mw = 8.0 - 4.5%. For all magnitudes, earthquakes are more common in southern California than in northern California.
Earthquake Hazards in California
- The likelihood of liquefaction, when partially saturated soil deposits can lose their grip completely with prolonged shaking, behaves like a liquid and loses its ability to support structures. The highest danger lies in low-lying areas, where there is loose sandy soil or poorly compacted artificial filling. A liquefied layer of sand can shoot to the surface with cracks, forming a sandstroke and precipitating the sand on the ground. This leads to permanent land reforms, such as lateral distribution and adjustment, which increase the likelihood of damage to buildings and infrastructure. Freedom areas for liquefaction include, but are not limited to, the southern Coachella valley and the upper basin of the Santa Ana River in southern California; The San Francisco Bay Area, northwestern Alameda County and the northern valley of Santa Clara in northern California, as predicted by the USGS.
- Susceptibility to landslides, where steep sloping areas covered with loose or soft rock are most susceptible to earthquakes caused by landslides, destroying buildings and other structures. Areasone to landslides include, but are not limited to, the eastern mountains of San Gabriel.
- Damage to the surface, where minor defects can break the surface of the earth when they are displaced against each other during an earthquake, which can cause serious damage to the building and infrastructure.
- Fires in which earthquakes in urban areas are often accompanied by devastating fires due to the rupture of gas lines and electrical flaws that can quickly spread due to clogged roads and destroyed bridges that impede firefighter access, or damaged water reservoirs that limit water for fire extinguishing. Without fires, losses and economic losses would have been halved.
- A tsunami where large earthquakes occurring in the Pacific Ocean can force out the ocean floor, creating a tsunami that could affect the West Coast.
There is a 62% chance that at least one earthquake Mw = 6.7 or more will occur in the San Francisco Bay area until 2032. The Hayward error has the highest probability of generating such an earthquake by 27%, while the northern part of San Andreas has a probability of 21%, Calaveras error is 11%, and San Gregorio error is 10%. It is well known that soft soils in the San Francisco Bay area will intensify and prolong shaking, even at large distances from the gap. Consequently, the repetition of the 1868 Hayward earthquake is expected to cause significant loss of life and intense damage to homes, businesses, transportation systems, and utilities. Several hundred thousand people are likely to be homeless after an earthquake. Expected economic losses in excess of $ 120 billion. USA. These losses include damage to buildings and contents, business interruption and living expenses, with over 90% of both residential and commercial losses being uninsured.
Southern California Oriented Economic Losses
A comprehensive 2008 study was conducted, known as the ShakeOut, USGS and CGS earthquake of a hypothetical earthquake Mw = 7.8, destroying the most southerly 200 miles from the San Andreas fault. Fracture rupture will result in more than 100 seconds of shaking through southern California. The event starts from the epicenter of Salton Sea, producing a very strong shaking due to the fault when it breaks, until it ends near Lake Hughes. The soil conditions at the sites along the fault will usually intensify the shaking of earthquakes. Deep soils in the sedimentary basin of Los Angeles will create constant shaking, as seismic waves are captured and reverberated. The intensity of shaking will also be strong in the San Bernardino Valley, in areas prone to landslides, mainly in the eastern San Gabriel mountains, and in areas unacceptable for significant liquefaction, mainly in the southern Coachella valley, where two conditions of liquefaction are used; strong shaking and high groundwater levels. However, localized liquefaction is likely to occur in the upper basins of the Santa Ana and Santa Clara rivers. In areas of strong shaking and liquefaction, the earth will move strongly back and forth; destroying thousands of old buildings, removing houses from the foundation and sending unsecured furniture and objects. Such an earthquake will cause about 1,800 deaths and 53,000 injuries. Fires are likely to occur. Estimated economic losses amount to 213 billion dollars. USA due to the shaking of earthquakes and, as a consequence, its consequences.
Get ready for ShakeOut
You must participate in the annual Californian seismic receiver ShakeOut. You can register on the ShakeOut website now to practice ShakeOut 2010 on October 21 at 10:21! This is a great opportunity to learn how to protect yourself and your family during earthquakes and get ready. More than 6.9 million California residents participated in the second annual earthquake exercise in 2009. They were reminded to maintain an earthquake preparedness plan, preparing an individual survival kit for each family member and a set of emergency situations for households, as well as storing emergency food and water for 1-2 weeks to prepare for the next inevitable earthquake. The 7.0 earthquake in Haiti demonstrates the need for earthquake preparedness for those who live in an active seismic region.
Interesting fact about California earthquake insurance
Homeowners insurance does not cover the earthquake in your home. It's amazing to know that 33% of homes were insured by earthquake insurance in 1996, when the devastating Northgeig earthquake in 1994 was still fresh in people's minds, but in 2006 only 12% of homes supported coverage, according to California Department of Insurance. Californians living in older homes must re-acquire earthquake insurance as an effective way to manage the potential costs of future inevitable earthquakes, especially after the 2010 Haiti earthquake.
Concluding remarks
The 2010 Haiti earthquake calls for Californians to develop, update or maintain their earthquake preparedness plans. If you live within a radius of 15 miles from active seismic faults and / or liquefied territory, you should reconsider the issue of retrofitting your home and moderating its contents in order to protect yourself and your family. The benefits of seismic modernization and mitigation far outweigh the mere reduction in financial loss. This will make your home safer and will help in returning your family much faster to returning to a normal lifestyle. In addition, re-examining earthquake insurance will help manage the potential costs of future earthquakes. Finally, develop an earthquake preparedness plan that includes maintaining emergency power and water for 1-2 weeks along with individual survival kits and a family emergency kit.
