posted on Feb, 19 2011 @ 08:35 PM
reply to post by antar
what is the difference between a quick jolt and and a long tremor?
According to the Mrs about 90 seconds
OK, we are talking about what you see on the seismograms rather than what is felt. A quick jolt is a local quake close to the seismo. The initial
'spike' goes straight up. You may see 2 parts a small version and then a large version, unless it is right on top of the quake in the which case the
spike will be straight up. This image shows on of the Arkansas ones on the 18th
Note that this one is done and dusted in a minute and a half.
A long tremor is when the quakes is further away and you mainly see the s-wave. In fact you may not even recognise the smaller p-wave. The longer ones
will tend to be the larger ones but that is not always the case.
If you look at Papua New Guinea on this one the flat start in the p-wave and then the slowly increasing wave is the s-wave. The whole thing rolls on
for more than an hour.
I f you go to This page
you will find information
about earthquakes and seismograms and the first link I recommend since I put it together!
It will explain exactly what happens with these
Puterman *waves* and goes to bed!
Just had to add that the type of strata in which the earthquake occurs, or which overlays the quake makes a very big
difference to the effect of the quake. The reason why New Madrid is potentially dangerous is not because of the size of the quake but because of the
effects as it rolls around in all that shale and water getting plenty of motion going. In a nice solid rocky area it is over and done with which is
why a man should not build his house on sandy ground. Mexico City has a problem in this respect. The effect of quakes there are amplified. Look up
Mercalli Intensity scale. This is not the same as the magnitude.
edit on 19/2/2011 by PuterMan because: (no reason given)