Question

The magnitude of an earthquake was defined in 1935 by Charles Richer with the expression M=log (I/S); where I is the intensity of the earthquake tremor and S is the intensity of a “threshold earthquake”.
(a) If the intensity of an earthquake is 10 times the intensity of a threshold earthquake, then what is its magnitude?
(b) If the magnitude of an earthquake registers 10 on the Richter scale, how many times is the intensity of this earthquake to that of a threshold earthquake?

Answer 1

Answer:

Step-by-step explanation:

a) Let the intensity of the earthquake be = I

Thus, I = 10 S

The magnitude of an earthquake is given byM = log 10S/S

Therefore, the magnitude of the earthquake will be M = log  I/S

= log 10

= 1

b) Let the number of times the intensity of the earthquake to that of a threshold  be =  x

Thus, the intensity of earthquake will be I = xS

M = log  I/S

Magnitude of the earthquake is M = log  xs/s  or M = log x

M = 10

Hence, log x = 10 and therefore x = 10`10

Answer 2

Answer:

Step-by-step explanation:

a) Let the intensity of the earthquake be = I

Thus, I = 10 S

The magnitude of an earthquake is given byM = log 10S/S

Therefore, the magnitude of the earthquake will be M = log I/S

= log 10

= 1

b) Let the number of times the intensity of the earthquake to that of a threshold be = x

Thus, the intensity of earthquake will be I = xS

M = log I/S

Magnitude of the earthquake is M = log xs/s or M = log x

M = 10

Hence, log x = 10 and therefore x = 10`10