Will there be a major earthquake in San Francisco soon?

Answer 1

Another Large Quake in the next 100 years? Maybe, but..."

Based on models taking into account the long-term rate of slip on the San Andreas fault and the amount of offset that occurred on the fault in 1906, the best guess is that 1906-type earthquakes occur at intervals of about 200 years.

Because of the time needed to accumulate slip equal to a 20 ft offset, there is only a small chance (about 2 percent) that such an earthquake could occur in the next 30 years, according to the report of the Working Group on California Earthquake Probabilities.

The real threat to the San Francisco Bay region over the next 30 years comes not from a 1906-type earthquake, but from smaller (magnitude about 7) earthquakes occurring on the Hayward fault, the Peninsula segment of the San Andreas fault, or the Rodgers Creek fault.

How soon is such an event likely to happen? Recent research offers some answers by providing new insights into the 1906 quake and the San Andreas Fault system. For example, geologists have dug trenches across the San Andreas Fault to find out how often very powerful temblors occur in Northern California. In these trenches, they have identified soil layers disrupted by a great earthquake before 1906. Charcoal in these layers has been shown to be about 400 years old. These and similar studies in Southern California, as well as thousands of years of historical records from China and Japan, tell us that giant earthquakes on faults like the San Andreas tend to occur every few hundred years. All this
evidence suggests that another shock as powerful as the 1906 earthquake is not likely to strike Northern California soon, probably not for at least 100 years.

Unfortunately, this reassuring result is balanced by other, more somber findings. Although a great earthquake is not expected soon, stress on the San Andreas Fault system has built up again after having been relieved by slippage in the 1906 shock. Seven decades of low seismic activity in Northern California ended with the occurrence between 1979 and 1984 of three quakes with magnitudes of about 6 and the occurrence in 1989 of the devastating Loma Prieta earthquake (magnitude 6.9). In the 70 years prior to the great 1906 quake, moderate earthquakes were common in the region, and shocks of magnitude 6 to 7 occurred every 10 to 15 years. Scientists believe that a similar period of strong quake activity may now be underway.

Because of extensive urban development in Northern California since 1906, the strong earthquakes expected in the coming decades may be very destructive. For example, a magnitude 7 earthquake occurring today on the Hayward Fault (a part of the San Andreas Fault system, along the densely populated eastern side of San Francisco Bay) would likely cause hundreds of deaths and almost $100 billion of damage. In 1999, the USGS reported that there is a 70% chance that one or more quakes of about magnitude 6.7 or larger will occur in the San Francisco Bay area before the year 2030.

Future strong temblors in Northern California are inevitable, but the damage they cause can be reduced significantly with adequate preparation. Studies of earthquake shaking, active faults, and the response of structures to shaking have already led to improved building codes and a better understanding of how to reduce the threat posed by earthquakes.

In 1990, the USGS, in close cooperation with the Red Cross, United Way, and many other contributors, created a magazine titled The Next Big Earthquake in the Bay Area May Come Sooner Than You Think—Are You Prepared? This magazine was distributed as a public service by 41 San Francisco Bay area newspapers to more than 2.5 million households. In addition to describing the earthquake risk, the publication advised residents on how to strengthen their homes and protect their families against earthquake shaking.

By studying quakes like the Great 1906 San Francisco Earthquake, scientists and engineers gain the knowledge and understanding necessary to assess the risk from future shocks and to reduce the vulnerability of buildings and other structures to damage in these inevitable and terrifying events. In this way they help to protect the lives and property of citizens of the United States.

Answer 2

http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/quakes_all.php

USGS is the best site to go to for progress in detecting an earthquake. I got you close to where you want to go virtually to see the status on LA.

I reciently asked a question about how to read a seizmometer and richter scales and he gave me some very good sources to look into. The answerer gave me a thorough answer. here are his sources.

Reading the seismograph is a big subject. You must know to differentiate between several forms of earthquake waves. The main waves are P wave and S waves generated from the point called focus. The L wave and R waves are surface waves generated at earth surface because of reflection and refraction. Richter scale will not give you the direct measurement of the magnitude of Richter scale. Even though I have good knowledge on earthquake and Tsunami I am not an expert in deciding the Richter scale magnitude by studying the seismograph. But the idea behind the calculation is you should find the distance of epicenter by seeing the arrival time of p wave and s wave. Roughly there will be a delay of 1 second for each 8 k/m distance. When you sense an earthquake of magnitude 3 in Richter scale at a distance of 100 k/m the shaking will be 0.1 mm. This will increase by ten fold for each Richter scale. The amplitude will get reduced by inverse square of the distance from epicenter. US GS site will provide free information on earthquakes.You can visit my site to have better knowledge on this subject.http://www.orkut.com/community.aspx?cmm=...
Presentation slides
http://asia.pg.photos.yahoo.com/ph/quake...

http://photos.yahoo.com/quakealert_no1...

Listen to this answerer he workes with the earley warning system.

Answer 3

Various unproved method for prediction.
Methods for prediction of earthquakes & Tsunami
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1. Seismic gape: - The earthquake at a particular place may occur for every fixed gape of time. By knowing the past records of the quakes affected at that place may help to decide when the earthquake is next due.

2. Planet position.: - When the stress is accumulated at the tectonic plate boundary and the same time if the position of more than 2 planets comes in a straight line this may help to accelerate the earthquakes. There fore the full moon days and new moon days are more vulnerable days for earthquakes. Some time this method fails why? Think of a sick patient. New moon and full moon days are dangerous for only sick patents. These days will not affect the healthy people. The same way if there is no accumulated stress at the tectonic plate boundaries no need to worry about the planet positions.

3. Sun rays falling method: - If you observe the position of the sun rays falling on our wall at a particular time on all days it should form an angular infinity symbol. If there is any deviation in its path it means that there is some difference in height of the earth. That means some strain noticed at that place. Somebody claims that they can predict the place of epicenter by observing this. The laser beam measuring method of earth height from satellite also will help.

4. MCDB:- Chinese scientist claims that they can predict up to 60 % accuracy by sensing electro magnetic rays.

5. Cloud forming: - Few hours to a few days before the occurrence of earthquakes a cloud reader claims that he has noticed a peculiar mosaic type of formation .We may also notice some lightening in the sky.

6. By sound :- A professor from Ajmeer University claims that he was able to hear a low frequency noise under 125 meter depth in a bore well. The same thing was reported by one Mr. Nair that he heard some roaring noise under the earth one week before the occurrence of earthquake in Gujarat.

7. By frequency of waves :- Mr Richter Allen of Berkley University claims that he can decide the magnitude of earthquake just 4 seconds after observing the frequency of the primary wave. Present method needs the full seismographic picture to find the real magnitude that too from as many places as possible to have fairly accurate results. His claim has got some truth because when there is a slip of bigger tectonic plate the frequency of quake will be less. If a small tectonic plate slips the frequency of the waves will be more.
8. There are several changes in nature and in the behaviors of animals and birds can be observed before an earthquake and Tsunami. I wrote several articles on these subjects. The water level in well may change. Stay away from beaches if you sense earthquake waves. The Tsunami may attack long after the shaking is stopped.






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Answer 4

That article is hilarious. You do realize LaBarbera is the spokesman for Americans for Truth About Homosexuality? This is a group that has jumped on the bandwagon boycotting Miller beer for their sponsorship of a community event. Read what this guy says. It's pure vitriol. That harpy goes on to say,"...the Marines, the symbol of all that is good in America..." are being held at bay while a homosexual community hosts an annual parade containing homosexuals. Why is a religious person so pro-military? The article also quotes the policy director for Concerned Women for America, Matt Barber. (A woman named Matt?) This is the group whose goal it is to, "bring Biblical principles into all levels of public policy." In other words, they want the US to be a theocracy. So religious fundamentalists don't like homosexuals? This isn't news. Does anyone know the other side of the story? Why would the Marines want to film on a street during rush hour? They eventually filmed elsewhere in the city, so they weren't denied a permit, they were just denied a permit to film on the street.

Answer 5

Yes, soon. Of course, soon is a relative term, but to a geologist, one million years ago was "soon".

Answer 6

Might be or might not 'cause the weather migh change or the plates might move