If earthquakes are not predicitable, why do siesmologists bother to study them?

On 11 March, a magnitude-9.0 earthquake, one of the largest ever recorded, struck with no apparent warning off the coast of Sendai, Japan. New Scientist explains why earthquakes are so hard to predict, how seismologists have tried to foretell quakes in the past, and what promising approaches may lead to successful prediction in the future.

Can earthquakes be predicted?

No – at least not so that we could issue an advanced warning for a specific time at a specific location that would allow for an orderly evacuation. Most quakes do, however, occur in predictable locations along well known fault zones, as was the case with last week’s megathrust off the coast of Japan.

How close can we come to predicting earthquakes?

For places with a high rate of historic activity, the chance that a quake will hit in a future period of several decades can be quite high. “We have models that say in southern California over the next 30 years, the odds of having an earthquake of magnitude 7.5 or greater is 38 per cent,” says Thomas Jordan, director of the Southern California Earthquake Center and a member of the Collaboratory for the Study of Earthquake Predictability. If the same models are used to calculate the chance of an earthquake occurring in southern California within the next week, the odds drop to roughly 0.02 percent, Jordan says.

Read more: https://www.newscientist.com/article/dn20243-why-earthquakes-are-hard-to-predict/#ixzz79Qz1xtpT.

Explanation:

You need to know why they happen so that they can be detected before they happen to save other people's lives.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

it is the most commonly accepted one