Regarding earthquakes...and scientific warning signs...?

Question

Years ago, I was under the impression that the devices used for detecting earthquakes was supposed to assist geologists and scientists to monitor earthquakes in such a way that a larger earthquake was pending or most likely to occur. What happened with that?. All they 'seem' to do it tell us we had an earthquake at Xrichter scale and where it came from. Which is duh, obvious. And we all feel the earthquake so why the need to use these devices if there is no helpful warning system?

Answer 1

In Japan there is now a working early-warning system that can detect an earthquake immediately after it takes place and inform people that the ground is about to start shaking. This system detects P-waves in the immediate aftermath of a temblor and informs people that the destructive S-waves are coming. This groundbreaking Japanese system has been widely publicised on TV and in other media and many Japanese have high hopes for the system.

Accurate short term predictions are the goal of today's researchers. The Japanese and Americans have invested heavily in computer technology to constantly monitor and analyse seismic activity. Every year over 150,000 earthquakes are recorded world wide. As much detail as possible is gathered from the world wide network of seismometers, which, incidentally, were set up to monitor nuclear testing not earthquakes.  

Answer 2

Recently there was a discovery that the atmospheric pressure in mines, caves and such change just before an earthquake occurs.  It was being researched as a way to predict.   I think the study was in California.  I don't remember the full details but you could research it.  

Answer 3

Most seismologists do not like to use the word prediction when it comes to earthquakes; the devices you are referencing are probably from the experiments in Parkfield of which none were effective. Most current work in earthquake forecasting (e.g. probabilities akin to weather) concentrate on depicting the stress/strain field of an active region where the areas of highest stress have the most probability to rupture (create an earthquake). Other current early warning work comes from the Caltech group (James Davis); the work concentrates on real time analysis of seismic data of large ruptures in California to provide ~1 minute warning to the LA area of the arrival of the shear waves. The other avenue of current work is based out of Rice U and the Carnegie Institute DTM (Niu and Silver) where there has been observations of changes in the fault rock properties before an earthquake. This observation is in the process of being confirmed and any benefit from this work is ~20 years out.

As far as measuring earthquakes, the devices used are seismometers. Without this equipment you would not be able to triangulate the travel times to determine the location or magnitude of the earthquake. These devices are also important for gathering data that can be used by seismologists to study the structure and dynamics of the solid earth (crust, mantle, and core). From a scientific standpoint these instruments are crucial to the science as it provides data to test hypotheses. Also the Caltech method does require seismometers to detect a large earthquake to trigger a warning.

BTW the Richter scale is no longer used as a standard measure of magnitude the more common measure is Moment magnitude for large earthquakes.

Answer 4

It's all part of monitoring and trying to find a median that could maybe help predict in the future. How do you expect them to figure out something without research? That is all they are doing.