Why did the San Francisco earthquake happen?

Answer 1

The San Andreas Fault runs through California where two underground plates meet. These tectonic plates can move inward/outward, up/down, sideways. Once these move, things on the surface move, too.

Answer 2

On the morning of April 18, 1906, a massive earthquake shook San Francisco, California. Though the quake lasted less than a minute, its immediate impact was disastrous. The earthquake also ignited several fires around the city that burned for three days and destroyed nearly 500 city blocks.

Answer 3

It happened in 1906. It was due to the fact that much of California is situated on the San Andreas Fault. Earthquakes happen in California regularly, though there hasn't been one as big as the 1906 one since then. It could happen at any time.

Answer 4

The city of San Francisco was constructed in very close proximity to a transform boundary where two differing tectonic plates (the Pacific and North American plates) are sliding past each other.

The relative motions of the two plates mean that they don't slide perfectly past each other, but push against each other as well. This causes compressional stresses to develop in the crust leading to deformations and the build up of elastic strain energy in the crust.

Ultimately the stress will exceed the strength of the rock mass or crust around the fault zone and the fault will "rupture" leading to a sudden brittle deformation and movement. The stored elastic strain energy is released all in one go and produces seismic waves that cause earthquakes.

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Answer 5

San Francisco is located along the San Andreas fault. This fault runs through the entire state of CA with smaller faults branching off as well. So, when it moves earthquakes happen along the fault and in places like San Francisco. Not all earthquakes in the state are felt or destructive and there are small ones happening all the time. One of the problems with San Francisco is that a large part of the city is built on land fill that was begun in the 1800's to make room for the gold rush population explosion, so there is no stable foundation under the buildings to keep them from shifting or falling down. Gold rush ships that were abandoned in the harbor have been found under building foundations when new buildings have been put up. The destruction is much worse because of this factor when an earthquake happens. Many of the buildings also date back to the 1800's and some managed to survive the 1906 earthquake and still have damage from that quake. The city has tried to retrofit and fix this problem, but there are still parts of the city that have damage. Even the City Hall still has a crack it in it from 1906. The city sits on a ticking time bomb, but when you are there you don't even think about it since it is a wonderful city.

Answer 6

The collision between the Pacific and North American plates

Answer 7

the San Fransisco earthquake was caused because there was a shift in the tectonic plates along the San Andrea fault.

Answer 8

The 1906 earthquake was caused by rupture of a 296 mile section of the San Andreas fault.