EARTHQUAKES
THE FUTURE OF CALIFORNIA
California, the Western-most State in America, is in acute danger of a major earthquake. Scientists have known this for decades. All the geological and seismological data show that a big earthquake in the West Coast is a matter of time. They in fact are amazed that such an earthquake has
not happened several years after its prediction. Although minor earthquakes and tremors occur all the time in different parts of California and the coastal islands, the people are no longer scared of the expected Big One, as they call it. They have just gotten used to the fact, or, perhaps, they wonder where to go and leave their wealth since California is America's Golden State. Read more at: https://danelite.blogspot.com.ng/
not happened several years after its prediction. Although minor earthquakes and tremors occur all the time in different parts of California and the coastal islands, the people are no longer scared of the expected Big One, as they call it. They have just gotten used to the fact, or, perhaps, they wonder where to go and leave their wealth since California is America's Golden State. Read more at: https://danelite.blogspot.com.ng/
This is California! The red and yellow lines in the maps (left) are lines of serious geologic faults which are predicted to have 99.7% chance of snapping at any moment.
Scientists believe that it is only a matter of time before an earthquake strikes Southern California that is large enough to cause damage throughout the entire region. In fact, after the March 2011 earthquake in Japan, scientists said the tsunami was heading for the West Coast and that California is next. Now the most comprehensive statewide analysis of earthquake probabilities has determined that the chance of having such a major and destructive earthquake in California over the next 30 years is 99.7%. Building on previous studies, the new model combined information from seismology, earthquake geology, and geodesy.
The official earthquake forecasts, known as the "Uniform California Earthquake Rupture Forecast (UCERF)," were developed by a multidisciplinary group of scientists and engineers, known as the Working Group on California Earthquake Probabilities. An independent scientific review panel, as well as the California and National Earthquake Prediction Evaluation Councils, have evaluated the new UCERF study. Starkly, there is a consensus among the scientific community on these forecasts. The results of the UCERF study serve as a reminder that all Californians live in earthquake country and should be prepared. Although earthquakes cannot be prevented, the damage they do can be greatly reduced through prudent planning and preparedness. The ongoing work in evaluating earthquake probabilities is part of the National Earthquake Hazard Reduction Program's efforts to safeguard lives and property from the expected future quakes. Read more at: https://danelite.blogspot.com.ng/
It is the basis of The Great Southern California Shake-Out Earthquake Scenario, the largest earthquake readiness campaign in U.S. history. The maps above show the areas in California with the biggest geologic faults and earthquake risks. These include Los Angeles, Ventura, San Francisco, San Andreas, Santa Barbara, Imperial County, San Diego, Riverside, Coachella Valley, San Bernardino, Cajon Pass and the northwest as far as Lake Hughes west of Lancaster. Although the forecast is projected up to the next 30 years, some scientists say “It could happen in the next five minutes or next five years”.
The official earthquake forecasts, known as the "Uniform California Earthquake Rupture Forecast (UCERF)," were developed by a multidisciplinary group of scientists and engineers, known as the Working Group on California Earthquake Probabilities. An independent scientific review panel, as well as the California and National Earthquake Prediction Evaluation Councils, have evaluated the new UCERF study. Starkly, there is a consensus among the scientific community on these forecasts. The results of the UCERF study serve as a reminder that all Californians live in earthquake country and should be prepared. Although earthquakes cannot be prevented, the damage they do can be greatly reduced through prudent planning and preparedness. The ongoing work in evaluating earthquake probabilities is part of the National Earthquake Hazard Reduction Program's efforts to safeguard lives and property from the expected future quakes. Read more at: https://danelite.blogspot.com.ng/
It is the basis of The Great Southern California Shake-Out Earthquake Scenario, the largest earthquake readiness campaign in U.S. history. The maps above show the areas in California with the biggest geologic faults and earthquake risks. These include Los Angeles, Ventura, San Francisco, San Andreas, Santa Barbara, Imperial County, San Diego, Riverside, Coachella Valley, San Bernardino, Cajon Pass and the northwest as far as Lake Hughes west of Lancaster. Although the forecast is projected up to the next 30 years, some scientists say “It could happen in the next five minutes or next five years”.
Read more at: https://danelite.blogspot.com.ng/
California and the Ring of Fire
Minor earthquakes occur nearly constantly around the world. But most of the world's earthquakes (90%, and 81% of the largest) take place in the 40,000 km stretch of seismic belt known as the Pacific Ring of Fire. The entire West Coast of California lies within this Ring of Fire. With the rapid growth of mega-cities such as Los Angeles, Mexico City, Tokyo, and Tehran, in areas of high seismic risk, some seismologists are warning that a single quake may claim the lives of up to 3 million people. In fact, geologically, California sits on the continental divide and any major earthquake there will be felt around the world. Newly published research reviews some of the early evidence scientists unearthed in California, toward the southern end of the fault which is known as the Cascadia Subduction Zone.
It's a long, tectonic boundary where the Juan de Fuca plate, lying beneath the Pacific Ocean, is shoving itself beneath the North American plate. When the Juan de Fuca plate suddenly lurches deeper, on account of stress, that's all: a devastating earthquake will occur! A tsunami of water may overrun hundreds of kilometres of land and submerge buildings. When a subduction earthquake occurs, the edges of the top plate often drop a bit, since the underlying plate that has been pressing up against it for centuries suddenly jolts deeper toward the Earth's interior. "[The land] drops back down because the stress is released," said David Valentine, a programmer at the University of California, San Diego's supercomputing centre, and lead author on the paper. The size of that drop is an indicator of the magnitude of the earthquake, Valentine told OurAmazingPlanet.
What is an Earthquake?
An earthquake is the shaking of the surface of the Earth at a particular location due to unequal forces in the earth's crust beneath. They are caused mostly by rupture of geological faults (cracks and shifts in earth's crust). The point of initial rupture is called the focus or hypocentre while the point at ground level directly above the hypocentre is called the epicentre. These cracks and shifts are known as tectonics. When the epicentre (break-out centre) of a large earthquake is located offshore (in the ocean), the seabed may be displaced sufficiently to cause a tsunami (speed flooding). Earthquakes can occur over a ground distance of 50-100km (e.g. Japan earthquake, 2011 and Alaska earthquake, 1964). The San Andreas geologic fault of California stretches over 300km along the West Coast! This means that the entire State of California is in danger. Read more at: https://danelite.blogspot.com.ng/
Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to toss people around and destroy whole cities. Seismic activity of an area refers to the frequency, type and size of shaking experienced in it over a period of time. Seismometers are instruments for measuring the speed and intensity of waves as they go through rocks. These intensities number from 1 to over 10. The Richter Scale (for intensities lower than 5) and the Moment Magnitude Scale (for intensities larger than 5) are the commonest measures. These two are numerically similar but the MM Scale is more advanced. Magnitude 3 or lower earthquakes are mostly imperceptible or weak and magnitude 7 and over potentially causes serious damage over larger areas, depending on depth. For every unit increase in magnitude, there is a roughly thirtyfold increase in the energy released. For instance, an earthquake of magnitude 6.0 releases approximately 30 times more energy than a 5.0 magnitude earthquake and a 7.0 magnitude earthquake releases 900 times (30 × 30) more energy than a 5.0 magnitude of earthquake. An 8.6 magnitude earthquake releases the same amount of energy as 10,000 atomic bombs like those used in World War II.
Earthquakes may follow each other successively in a place. An aftershock is an earthquake that occurs after a previous earthquake known as the mainshock. An aftershock is in the same region of the main shock but always of a smaller magnitude. If an aftershock is larger than the main shock, the aftershock is re-designated as the main shock and the original main shock is re-designated as a foreshock. Aftershocks are formed as the crust around the displaced fault plane adjusts to the effects of the main shock. Earthquake swarms are successive earthquakes striking an area within a short period of time. In August 2012, a swarm of earthquakes shook Southern California's Imperial Valley, the most recorded shaking in the area since the 1970s. Read more at: https://danelite.blogspot.com.ng/
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