Earthquake Question

I don't have any answers but this is an interesting question. Are you just "in the know" on technical details, or are there web sites that make the magnitude and frequency in X,Y,Z directions at different locations available to the general public?

I described the event as to my recollection. There are however, dedicated web-sites, which log every such event on earth according to collected local databases, and their records go way back to the start of the last century, so the event I described must appear there - I'll look for the official reference - I only managed to have this yet.

I also know there are underground bouncing waves, kind of echo to the primary shockwave - these cause the aftershock if I understand it correctly, but I'm not knowledgeable in this - just a curious party.

shalom Yuval

I think that better you ask ex-israeli professor emeritus from Stanford university Amos Nur who is one of the world's leading experts in geophysics,specialising in earhquakes.

CraziestOzzy

Well done CO. GA from me. Although very complex this should give a good idea were to go if concerned with these matters. The mentioning of the micro and macro scales was quiet refreshing, because it fits other physical and human extremes of behavior as well.

It should be an IA (Inspiring Answer) instead of a GA (Good Answer) but what the heck, your a Queenslander, you deserve it any way.

Greetings, Ky.

Hi Yuval my part of the rock is rather stable except for the sinkholes.

Therefore rather clueless but extremely inquisitive.

Is it not possible that you were close to the epicentre of another minor simultaneous event with another signature?

Not any such recorded event that I know of.

P.S

1. There are a lot of deep sinkholes in the vicinity of the Dead-Sea in the South-East.

2. Keep in mind that the whole of Israel is about the size of Lesotho. Heck, the whole north of Israel is about the size of Johannesburg, if you include Alexandra and Soweto - I should know, I lived there (in Yeoville) for a few years.

3. The whole of Africa is very stable because it is in the middle of a plate - Israel is squeezed between the Euro and Asian plates, I think they're called "The African" and The Australian" plates, respectively, but I'm not sure

What about the concept that mass absorbs shock waves? The mountain's mass could have absorbed and slowed down those propagating shock waves, compared with the unbuffered impact on the lowlands.

The seismic event would have been propagating horizontally on the level below the lowlands. Vertical distance is another factor that might account for why the shock would be less high on the mountain. (Of course, if the mountain is at all unstable, or the shock is strong enough to destabilize and cause landslides, it could be a worse place to be in an earthquake).

Yuval,

The eastern Mediterranean is the meeting place of three major tectonic plates, Arabia, Nubia, and Eurasia and two sub-plates Anatolia and Sinai. Although global-wise it is a relatively small region (2% of the Earth's surface), it is tectonically very interesting as containing a variety of tectonic environments. The Red Sea, which separates between Nubia and Arabia, represents a unique environment of mature continental rift or embryonic ocean. Continental collision between Arabia and Eurasia occurs in the Caucuses, which are located between the Black and the Caspian Seas. Oceanic collision occurs along the Hellenic and Cyprian Arcs, as the Nubian plate subducts beneath Anatolia. Transcurrent movements occur along the Dead Sea Fault, the North Anatolian Fault and the East Anatolian Fault, as the smaller plates accommodates some of the oblique motion between the three major plates.
The Dead Sea Fault is a transform plate boundary separating the Arabian plate from the Sinai sub-plate. It transforms the Arabia-Africa divergent motion in the Red Sea into the convergence motion between Eurasia and Arabia, currently expressed by extrusion of Anatolia. However, not all the African-Arabian divergent motion is transferred northward to the convergence zones. Some of the divergent motion in the Red Sea propagates into the Gulf of Suez, which forms the southwestern boundary between Africa and Sinai. North of the Gulf, the Africa-Sinai boundary is diffuse and hard to allocate. Additional divergent motion is taken up by secondary faults branching off the main trace of the Dead Sea Fault north of the Dead Sea. The activity along the Dead Sea Fault has been continuous since the Miocene to the present. The total displacement across the southern section of the Dead Sea Fault (south of 32°N) was estimated as 105 km, whereas across the northern section the estimated displacement is significantly less.

The Dead Sea Fault is subjected to a moderate level of seismicity. The highest recorded seismic activity was in the Gulf of Elat (Aqaba), the location of the 1995 Nuweiba earthquake. Another area of concentrated activity is the area of the Dead Sea, where the M=6.5, 1927 Jericho earthquake occurred. Seismic activity along the Arava Valley, which is located between the Gulf of Elat (Aqaba) and the Dead Sea, is very limited. North of the Dead Sea, seismic activity is distributed over a wide area, reflecting diffuse deformation in northern Israel and Lebanon.
There is a fault branching from the Dead Sea Fault that goes under Mount Carmel to the Mediterranean.

Jon

Thanks RHABE, this is about what I was curious to learn.

So, shockwave travels through elastic medium might change frequency and waveform according to what, relative density of the medium ?

http://neic.usgs.gov/neis/eq_depot/2004/eq_040211/neic_etal_ts.html

on the region

http://earthquake.usgs.gov/eqcenter/eqinthenews/2009/

it doesn't appear in this list

http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/quakes_big.php

or this one, but it's a great site if you didn't know about it

http://earthquake.usgs.gov/

start here

An amazing array of intelligent answers to your question. Here is my attempt. At the epicenter there is a huge and rapid release of stored up elastic energy. This represents a shock wave that propogates in all directions. When this shock wave interacts with a structure, it excites the structure at the resonant frequency of the structure. If the structure is a small house in a valley, its frequency might be 1.0 cycle/sec. If the structure is a tall skyscraper, its frquency micht be 0.1 cycle/sec. A mountain might have a frequency somewhere between these two structures. Of course, a scientific answer would include terms such as Q, damping, etc., but I think that the resonant frequency of your mountain determines its response to a shock wave.