Page 25 - Jabalpur_EQ

Chapter 2 Seismological Aspects

TABLE 2-2. Fault Plane Solution of the Jabalpur Earthquake
(USGS)

Strike Dip Slip
NP1 280 25 124
NP2 63 70 75

CHARACTERISTICS OF EARTHQUAKE

Sound
The earthquake was accompanied by perceptible sound which was mainly con-
fined in the meizoseismal area. The reported perception of the sound was vividly
described as passing of a train over a bridge, passing of a truck or bulldozer,or
passing of a helicopter or airplane. Table 2-3 contains the description of soundas
reported by people in various villages. It should be noted that earthquake sounds
generally appear to be dominated by sounds related to structural effects. There is
a common reporting that sound precedes the shock and is generally true for 58 to
72 percent of the cases worldwide. It is generally observed that as the distance
from the hypocenter increases, the sound tends to become more smoother and
monotonous. The sound generating from ground is due to seismic motion related
to P and SV waves which get converted to audible acoustic pressure waves at the
earth surface.

TABLE 2-3. Sound Associated with Jabalpur Earthquake

Village Name Perception of Sound
-
Kodariya Rumbling sound like a passing truck
Chhattarpur Like passing of an airplane

Bheraghat Like passing of a train or bulldozer
Shahpura Like a helicopter
Nohta Like a grinding mill (chakki)
Garhakota Rumbling sound

Goshalpur Like passing of a train
Dharau Like passing of a train
Salimanabad Like passing of a train over a bridge
Katangi Like an operating concrete mixer
Bhuri
Like passing of an airplane

Duration of shaking

Duration of strong ground shaking is an important parameter as damage to struc
tures is directly related to duration of strong shaking. Normally strong motion

Jabalpur Earthquake of May 22, 1997 15