Question

The magnitude, M, of an earthquake is defined to be M=log I/S, where I is the intensity of the earthquake (measured by the amplitude of the seismograph wave) and S is the intensity of a “standard” earthquake, which is barely detectable. What is the magnitude of an earthquake that is 35 times more intense than a standard earthquake? Use a calculator. Round your answer to the nearest tenth.

–1.5?
–0.5?
1.5?
3.6?

Answer 1

Given:
M = log I/S

M = magnitude
I = intensity of the earthquake
S = intensity of the standard earthquake

The minimum intensity of a standard earthquake is 10.
Intensity of the earthquake is 35 times the standard earthquake. So,
10 x 35 = 350

M = log 350/10
M = log 35
M = 1.544 or 1.5  Third option

Answer 2

the answer is 1.5 have a good day