Question

In a cross hole test, the trigger and geophones are 5m apart. After impact, the arrival time of SV wave at geophone is 20 msec. The velocity of SV wave is

Answer 1

distance between trigger and geophone = 5m
after impact, time taken to arrive SV wave at geophone = 20mSec

we know, 1 milisec = 10^-3 sec
so, 20mSec = 20 × 10^-3 sec

now, the velocity of SV wave = distance between trigger and geophone/time taken to arrive at geophone
= 5m/(20 × 10^-3 sec)
= 250 m/sec

hence,speed of SV wave = 250 m/s

Answer 2

t = arrival time for sv wave to reach geophone = 2 m sec = 2 x 10⁻³ sec

(since 1 milli = 10⁻³ )

d = distance between trigger and geophones = 5 m

v = speed of sv wave

the relation between speed , time and distance is given as

v = d/t

inserting the values

v = 5 m/(2 x 10⁻³ sec)

v = 2500 m/s