seismic signal detection...

[arpita]

hi everyone.....
i m working on seismic signal detection....i wanted to know whether or not it is possilble to detect seismic signal before they cause any destruction......if yes,..how is it done ....is it possible to prepare a model of it....????

do help .....
thnks...:

 

[Nigel Goodwin]

It's been done for well over a hundred years, check here:

https://en.wikipedia.org/wiki/Seismometer

Detection before a quake is a completely different matter though.

 

[arpita]

thnks...but i wanted to know is it possible to evacuate a place as soon as an earthquake is sensed......i mean....is the earthquake sensed before the waves strike the surface.....secondly....what are the analysis done after an earthquake has occured......what are the utilities of those anlysis.....?????

 

[Nigel Goodwin]

I suggest you google for information, there's a LOT of work done along these lines in America, as they have some of the most at risk cities in the world.

But as far as I'm aware there's (as yet) no way to sense a quake in time to do anything about it.

 

[arpita]

but .....what are the analysis done afterwards even though we cant sense the earthquake but what use are the analysis!!!!!!!!!!!!!!!!!!

 

[Nigel Goodwin]

How would I know?, like I said, you should be able to find plenty of information from America via google.

 

[mneary]

The easiest way for a novice to sense an earthquake 'in advance' is to sense the P-wave. The P-wave travels faster than the S-wave. The P-wave is often a single hit, making it common to some other local disturbances (like a vehicle hitting a light pole).

The S-wave is more sustained, and does much of the damage. It comes later.

Now the bad news: These waves move fast. 5000 m/s is quoted for the p-wave speed in granite. S-waves are quoted as 60% of that. [citation]

Further bad news: You get no warning when you are near the epicenter; the only meaningful warning you get is when you are a long distance away and you are in less danger. If you're 20 miles away, your advance warning could be four seconds. iirc, that's about what I had for the 1994 Northridge quake.

A region-wide seismic sensing system could have increased that warning (for me) to almost 10 seconds. But it didn't matter, we were not at significant risk.

Generally, evacuating a building before (during) an earthquake is a Very Bad Idea. Long before the building collapses (if indeed it ever will) the window glass is showered everywhere, including the exits.

 

[arpita]

i do agree with u mneary...but what use are the analysis done afterwards when the earthquake has already occured.......do replyyyyyyy

 

[mneary]

Analysis is for learning.... to find other things that we do not know.

We use this all of the time in industry.

 

[arpita]

can u give me some examples...like what other things are studied...and how are they used...?????/

 

[blueroomelectronics]

Guess there are no earthquaka forums.