How can it be in Seismic zone but not in earthquake zone or near earthquake fault?

Question

Area between North San Jose and Milpitas.
Is being Seismic zone more dangerous than near an earthquake fault? When will seismic liquefaction happens? Does it have to be with or without every earthquake?

Answer 1

~d1hossain is close. What you need to check out is "tectonic" plates and tectonic mechanics/physics. You might also want to look into seismology, volcanism, and diastrophism. As for the relative danger zones, you might want to look into tsunamis and other seismic displacements. "Nearness" to a fault is relative in the world of geology. Few places on earth are not "near" a fault and safe from the effects of a cataclysmic underslide, as evidenced by the Rockies and the Himalayas.
That's all of your homework I'll do for you. If it isn't homework, and you are asking out of genuine curiosity, all the more reason to do your own reasearch. It's called learning.

Answer 2

But you are near faults...lots of them. You might not be sitting on a fault directly but you're still effected by the multiple nearby faults. I think the term Seismic zone is used because you are near at least 4 faults in the San Jose area and at high risk for seismic activities. It's not anymore dangerous than living near an earthquake fault. There's just a risk involved.

Seismic liquifaction occurs when the shockwaves of an intense earthquake (high 7 or 8) cause the top layers of sediment to act as a liquid, usually partially swallowing houses and whatnot. Depends on how much sediment is between you and the bedrock. And it doesn't happen with every earthquake. Just really intense earthquakes, and usually the longer earthquakes. Most only last a few seconds.

Answer 3

Seismic zones are not the place where the earthquake will affect. The seismic zones are the place where the damage will be severe during earthquake. So many geological factor decides this. The damage need not be high near the epicenter of earthquake. Last year when I was in Singapore we experienced the earthquake. They are having about 7 seismic stations in Singapore. But the seismic waves were recorded at two stations only.Those places are located in reclaimed land.The soil condition may amplify the shaking. By A.Ganapathy researcher on earthquake.

Answer 4

I don't know the specific of the area you are describing.

But, there are seismic zones that can amplify the amplitude of the earthquake causing larger damage to buildings and people. Mexico City is the classical example of a city built in such a setting. Mexico city was built on a dried lake in which the sedimentary basin can amplify the amplitude of the waves generated by an earthquake. It reacts in resonance to the seismic perturbation. In this case areas closer to the epicenter (but outside the paleolake) are less damaged than areas inside the paleolake.

Liquefaction happen in areas where you have poorly consolidated sediments that contain water (for example close to a beach or in areas inside a sedimentary basin). Affects mostly to sandstones.
Liquefaction is used to extract air bubbles from concrete when is being poured. When a vibrator is applied to the concrete, it becomes a liquid of low viscosity allowing air bubbles to scape. When the vibration stops the concrete becomes a high density fluid until it solidifies.

Answer 5

Not 100% about what you are asking but I know that there are 2 major fault lines in California. One is the San Andreas and the other is in the Pacific ( I forgot what it is called). Both are ready for huge quakes. Seismologists have said that big "ones" (over 8.0) happen ever 300 to 350 years. Core samples from the Pacific indicate that one(over 8.0) very large one hit sometime around the 1700's. There is proof in Japan of a tsunami (that had a wave about the size that struck in 04) back in the 1700's but there was no quake. I am not sure about the seismic factors though. I think that it may be more of an aftershock thing, but I am not sure.I hope that that helps you a bit.

Answer 6

you don't have to be next to a fault line that has ruptured to feel an earthquake, you can be hundreds of miles away and still feel the effects, so im guessing not all earthquakes occur in or near fault lines in the second question California does not experience the worst Earthquakes in the USA even though every week there are hundreds of minor Earthquakes. Alaska comes first then California. but Northern California experienced the effects of the 9.0 Earthquake in Cascadia Subduction Zone in 1700. but Alaska had a 9.2 Earthquake in 1964 the biggest in California was a 8.0 in 1857

Answer 7

,your talking about the San Andres fault ,it is on the move all the time, you can't see it moving ,this fault runs the Leigh of California,all faults have a potential danger zone that can move at any time, when L.A. had there last, the ground moved putting pressure on another area and some day that area will move to see all this better go on line look for satellite images of the San Andreas fault it can be seen clearly from above,no one can tell at this when any fault is going to move but there working on it getting much better look in Mt St Helen

Answer 8

this is not going to be a tech answer to your q but more my observations in regard to earthquake prediction. I worked in South Africa as a gold mining geoloigst,and due to the depth of mining rock stress ws pretty high and "bumps" were pretty common .Bumps are rock burst related to mining activity and they often registered over 1 on the Rithtcer and we had rock mechanics and sesimic enigneers and their true accurate was so hit and miss in prediction(they were excllent at telling us about bumps after they had ooccured) that i often suggested we replace them with animals , whose seem to be able to predict siesmic events. Maybe Singapore shore put a few cows every few blocks and if the cows starting gettin g restless they would know an earthquake was iminent:))))))))

Answer 9

As it depends also on the layers and charactaristic of the earth plates as well as the nature of the tetronic plates