why is the shadow zone of an earthquake in japan different from the one of an earthquake in california?
926059
theyre on different plates
211905
The world is divided up into different plates, which move around ever so slowly. Sometimes they collide, and a mountain is formed as the sides of the plates hit each other and push upwards. This is how the Himalayas were formed, and they are getting higher as the plates slowly push against each other. Where two plates push past each other, an earthquake can result. This is the case along the San Andreas Fault. Hope this helps!
128316
Well, living in the shadow of it (as I do), it and the mountains around and behind it both absorb most of the heat that is blown across the island.  Thus, Tokyo, Yokohama, and the cities lying on the eastern coast of Honshu enjoy slightly colder but also clearer weather, with the mountains also causing most precipitation to condense.
113993
Yes. Earthquake activity in this region is due to plate tectonics. In Kashmir the two plates involved are the Eurasion and Indian tectonic plates. \n\nHere are a few good ways to demonstrate this for elementary school children:\n\n*Have them use their hands with thumbs hooked together and move push one hand forward while pulling one hand back. Force builds up, but when one of the thumbs breaks free both hands makes a big movement (earthquake).\n\n*make playdough "plates" and have slowly pushed together to see uplifting and subduction.\n\n*take model cars/trucks. Predict what would happen if they have met head-on and continue to move. Let cars represent oceanic plates (less dense) and trucks represent continental plates (more dense). This is a good visual to see uplifting (rumpled hoods when they are the same density--car/car or truck/truck) and subduction (truck runs over top of car).\n\nGreat website for kids is:\n\nhttp://earthquake.usgs.gov/learning/kids.php?\n\nGreat website for kids with links to many science websites is:\n\nhttp://members.tripod.com/~ozpk/00000science1-4\n\nHope this helps!
23698
An earthquake is a sudden and sometimes catastrophic movement of a part of the Earth's surface. Earthquakes result from the dynamic release of elastic strain energy that radiates seismic waves. Earthquakes typically result from the movement of faults, planar zones of deformation within the Earth's upper crust. The word earthquake is also widely used to indicate the source region itself. The Earth's lithosphere is a patch work of plates in slow but constant motion (see plate tectonics). Earthquakes occur where the stress resulting from the differential motion of these plates exceeds the strength of the crust. The highest stress (and possible weakest zones) are most often found at the boundaries of the tectonic plates and hence these locations are where the majority of earthquakes occur. Events located at plate boundaries are called interplate earthquakes; the less frequent events that occur in the interior of the lithospheric plates are called intraplate earthquakes (see New Madrid Seismic Zone). Earthquakes related to plate tectonics are called tectonic earthquakes. Most earthquakes are tectonic, but they also occur in volcanic regions and as the result of a number of anthropogenic sources, such as reservoir induced seismicity, mining and the removal or injection of fluids into the crust. Seismic waves including some strong enough to be felt by humans can also be caused by explosions (chemical or nuclear), landslides, and collapse of old mine shafts, though these sources are not strictly earthquakes.
607630
yea.. it's Helicorder Images, a way to record the earthquake in a given area.. even it is minimum. for reading of this, you need to do a bit study. surf the net, also go here:
1049212
Because San Fran is on a major fault line. That basically means that the ground below the streets isn't set properly so it fragments easily to make the Earth subside, and the Earthquakes to occur. I don't know why its like it in the 1st place though?
1050564
well city has tons of buildings and the buildings have weight. so they will add more pressure to the tectonic plates and cause them to move faster i guess. There are tectonic plates which meet at one point and they either slip, slide or grind agaisnt each other. and when they slip, this causes the earthquake. so then the more weight on the plates means also more pull. so the plates move faster or something. my guess. but i doubt it has any effect
396469
The path of the light (or shadow) is unrelated to the gravity.  Gravity of both bodies (sun and moon) is acting on the whole Earth, not just the area where the eclipse is seen, so earthquakes would not be related to the eclipse.  BTW: Tidal forces of the sun and moon happen all the time and alignments and oppositions will create extreme pulls.
516486
Small parts of California may fall into the ocean, but what is really happening--and has been happening for millions of years--is that a strip of western California is traveling northwest, relative to the rest of the continent which is moving southeast. The line between them is called the San Andreas Fault, and that's where many of the California earthquakes happen. \n\nI've seen a map that has that strip splitting off to form an island--or a very long penninsula like that by Baja California--in about 50 million years.
274586
There are areas that are more prone to Tsunamis than other areas.  Besides the seismic activity factor, the shape of the ocean floor has a lot to do with whether a tsunami hits a coastal area and how bad the tsunami is.  For example, in the 1964 Alaska earthquake, a tsunami wave went south and struck the California coast.  Damage ranged from minor (boats knocked against the dock) to devestating as in Crescent City where 30 city blocks were covered and 11 people died.  The seabed off of Crescent City forms a shallow slope the forces the pressure of the tsunami up into the classic "tidal wave" configuration associated with tsunamis.
422794
Whan an earthquake occurs, it sends shock waves through the earth. One travels through the earth's surface by compressing back and forth the rocks, the other by moving them up and down. These both travel at different but known speeds, so when an earthquake registers at a recording site it registers as two blips, a P wave blip first and an S wave blip later. The distance between these blips tells the seismologists how far away the earthquake was, the bigger the gap, the further the distance. To find the location of the earthquake you then need to use different recording sites data for how far away it was and triangulate the data to find an actual location of the epicentre. The waves also travel through the earth in different ways in addition to the p and the s waves, by going throught the surface or more directly through the earths core. Again the data for these echo times differences is known and allows a distance to the epicentre to be calculated.
74001
When the "Big One" hits LA, it is very possible that small (less than 1 square mile) portions of the cliffs from Santa Monica to Malibu may fall in the ocean, but NO catastrophic (i.e. a city-wide or state-wide collapse) can possibly occur.  The primary reason is that all rocks have a finite strength and ability to accumulate stress.  Rocks along any fault will fail (causing an earthquake) before they can accumulate the amount of stress required to generate an earthquake capable of causing anything outside a mile or so of the coast to fall into the ocean.  That is the reason you don't see earthquakes greater in magnitude than 9-9.5....because rocks break and release their energy in the form of an earthquake before they can accumulate the stress required for a magnitude 10 or greater.
950622
the tectonic plates that shift happen  underground, if your lucky to see a plate shift at ground level your truly lucky, these plate shifts cause earthquakes so please be careful.
403621
In a nutshell, their is no way to predict earthquakes because there are little to no warnings signs. For example in California, This is a transform fault where two plates are sliding past each other... Eventually the stress builds up so much that it moves a lot at one time.. This is what causes Earth Quakes there, and when they happen they are devastating... We just cant tell when the stress is so much that an earthquake is going to happen.. It is not possible and probably will never be.
234933
I can't think of any different, but been living here all my life in the bay area in Silicon Valley, Tri-Valley and the  Central Valley.  I like the Central Valley the best, because you don't really feel the Earthquake here.  What really puzzle me the most is high cost housing is in the wrong area because they are on the Earthquake foundations and all other areas in the east of the Bay Area is lower and little effects on Earthquakes.  My point is the Eastern side should cost more than the Western side of California because more safer from Earthquakes.  Any lands that is far side safer from earthquake shall be consider the highest in the house Market!  Funny the House Market should go back to school!
731013
Really, the answer to your question is simply: Plate Tectonics. Read below for details.\n\nEarthquakes: \nIt all comes down to stress and strain from the interaction of different plates, chiefly at the boundaries. It is not 'the plates rubbing together' as many people say; or at least that's a very simplistic view.\n\nPlate tectonics causes stress on the continents and oceans, all over the surface of the earth. In some places, the stress is very small (usually within the plates). Elsewhere, the stress is high, usually where the plates meet each other. Since each plate moves, when two come in contact, the stress each other. They can push on each other and cause compressional stress, they can pull with extensional stress, and they can slide past or shear each other with tensional stress.\n\nFaulting, causing earthquakes, comes from the fact that this stress is building up all the time, but rocks and continents are strong materials. Just like hitting a rock with a small hammer, you do put stress on it, but a small amount. It would take a sledgehammer to put enough strain (effects and accumulation of stress) to build up and cause breakage. In the earth, the area around an active fault builds up strain from the stress of plate tectonics. Most faults become locked, because of this strength, and thus can not release their strain. Away from the fault, the stress produces very small and slow movement of the rock masses as a whole. Eventually, the strain is too much and the rest of the plate has moved too far and the fault releases the strain build-up all at once in a big stress release called an earthquake. This is called the elastic rebound theory, and it explains most (but not all) movements.\n\nThis is why an earthquake's size is relative to the fault size. The bigger the fault, the bigger the strain build up, and the bigger the release in an earthquake. Subduction zones and collision zones, where large portions of plates actually can rub together as a whole, have the really big earthquakes, like the 2004 Sumatra earthquake. In other plate boundaries, the entire plate boundary does not act together, so the faults become spread out and many faults take up the strain from the tectonic stress, like with the San Andreas Fault in California (it only takes up ~3/4 of the stress between the plates).\n\nEarthquakes are really tricky things; there is still so much we need to learn. As of now, there is no way to predict them, but we can say where the danger is highest and about how long between events.\n\nVolcanoes:\nThere are several processes in Plate Tectonics that cause volcanism, but they result in two main types of volcanism.\n\nVolcanism in subduction is caused by volitals, like H2O, CO2. These are carried down by the plate, mainly in the form of weak minerals. These minerals break down with pressure and temperature into stronger minerals that don't contain water and carbon dioxide. The leftover gases and liquids travel into the mantle (the mantle wedge) and hydrate the mantle, causing melting. The melt rises and then... volcano!\n\nThe other main cause is from rising mantle material, which forms decompression melting. Basically, hot mantle is kept from melting by the pressure of the earth at depth. When this material rises, the pressure drops much faster than the temperature, and thus it partially melts. This mainly occurs at divergent boundaries and hot spots, which are areas in plate tectonics that have rising materials or spreading.\n\nMountain Belts:\n\nNon-volcanic mountain belts are caused by compressive stress in plate tectonics. This can be 1. fold and thrust belts in highly compressive subduction zones (almost always from oceanic beneath continental subduction, e.g. east Andes, Rockies) or 2. continental-continental collisions (e.g. Himalaya, Appalachian).