Question

I know this question has been asked before, but I must be missing something. Please help clarify... How is the geology of Japan similar to and different from the geology of the west coast of the US with regard to earthquake risk?

I understand that Japan sits on a large section of the ring of fire and that serious earthquakes have occurred and tsunamis have been triggered in the past. I also know that the west coast of the US has also dealt with earthquakes and triggered tsunamis in the past in relation to it being close to the Pacific rim. Earthquakes are hard to predict, but tsunamis can be if the correct data is gathered first. From there, I'm not grasping the entire question/information.

Answer 1

Earthquakes and tsunamis:

The geologies of the coasts of Japan and the west coast of the United States although they are part of the Pacific fire ring, are geologically very different because in Japan the oceanic crust subducts below the continental crust causing a chain of mountains and volcanoes trench (Mount Fuji, Mount Asama, Mount Ontake and Mount Aso, among others) and the deepest pits such as the Marianas while on the west coast of the US it does not happen that way and the geology is typical of transforming plate boundary with important failures such as Origin of earthquakes Both references produce earthquakes because they are very active plates due to the characteristic of being plate boundary, but the subsidence of the oceanic crust below the Eurasian plate produces greater seismic activity and because they originate in the ocean floor, tsunamis originate that later move this movement in its surface with very high waves causing disasters in the destination coasts, but on the west coast of the US the seismic activity is lower but it is also high risk.
And although earthquakes cannot be predicted, the frequency of movements are indications of measures for the calculation of earthquake risk and in the case of tsunamis, these earthquakes once originated on the seabed are detected by surveillance buoys as part of an early tsunami detection system offers the coast a few seconds of advantage to protect itself before the tsunami arrives at that coast.