Question

question 9 (1 point)
approximately how much more energy is released in a 6.5 richter magnitude earthquake than in one with magnitude 5.5?
3000 times
3 times
300 times
30 times
question 10 (1 point)
the mechanism by which rocks store and eventually release energy in the form of an earthquake is termed ________.
fault displacement
seismic rebound
elastic rebound
stress fracture

Explanation:

Step1: Use the energy - magnitude formula

The formula for the energy \(E\) released in an earthquake in terms of magnitude \(M\) is \(E = E_0\times10^{1.5M}\), where \(E_0\) is a constant. Let \(M_1 = 6.5\) and \(M_2=5.5\). Then \(E_1 = E_0\times10^{1.5\times6.5}\) and \(E_2 = E_0\times10^{1.5\times5.5}\).

Step2: Calculate the ratio \(\frac{E_1}{E_2}\)

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The elastic rebound theory explains that when rocks are deformed (stressed) over time, they store elastic energy. When the stress exceeds the strength of the rock, the rock fractures and rebounds (returns to its original shape in an idealized sense), releasing the stored energy as seismic waves (earthquake). Fault displacement is related to the movement along a fault plane. Seismic rebound is not the standard term. Stress fracture is a general term for rock breaking due to stress.

Answer:

30 times