Medvedev, 1961 used the product of the velocity of the longitudional wave (V p ) and density ( r ) of the material, the impedance as a basis for astimating the relative di fference in intensity, also rendered by the water content of the ground.
He determined that,
h = 1,67. [ log ( V s . r s ) log (V n . r n )] + e - 0.04 h2
where h is the increase in intensity on the GEOFIAN scale, for ground with characteristics r n and V n , with respect to standart ground (granite), with characteristics V s (5600 mps), and r s (2,9 gr/cm 3 ), and h equals depth of ground water level.
Increase in seismic intensity from the ground at the Holy City Makkah is about 2.
The increase in intensity h is given small unity, However , the recent earthquake results have shown that one unite increase in intensity associated with 20 times increase in structural damage.
For this reason, the microzonation map pf the Holy City Makkah shall be prepared immediately.
Since some historic and rececnt earthquakes have been recorded within the investigated area, preparation of the dynamic properties of the soil under the Al-Haram Ash-Sharif shall also be made.
Merghelani, 1979, suggested that some of the transform faults that may be capable of producing earthquakes large enough to cause damage in the heavily populated area.
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