EARTHQUAKE ENERGY RELEASE

Mark Gorenc Morgan Rosenberg

Earthquake Energy

• Potential energy is stored in the crust as build up stress • Earthquakes transform this potential energy into: cracks in rocks (deformation), heat through friction, radiated seismic energy (Es) • Can only measure seismic energy, using seismometers • Several million earthquakes occur in the world each year • Many go undetected because they hit remote areas or have very small magnitudes

Energy Equations

• log Es = 4.8+(1.5Me) • Me = Energy Magnitude (seismometer reading) • Es = Seismic Energy (in joules) • So, to solve for Seismic Energy: • Es = 10 ^ (4.8+1.5Me)

Earthquake Energy

Magnitude

8.0 to 9.1

7.0 to 7.9

Annual Average of Frequency 2000 to 2008

1 13 6.0 to 6.9

5.0 to 5.9

4.0 to 4.9

3.0 to 3.9

145 1,526 10,557 100,000 2.0 to 2.9

1.0 to 1.9

1,000,000 10,000,000 0.1 to 0.9 100,000,000

TOTAL 111,112,242 Minimum Energy Released Annually (J)

8.4E+16 2.5E+16 9.1E+15 3.0E+15 6.7E+14 2.0E+14 6.3E+13 2.0E+13 8.9E+12

1.2E+17 Maximum Energy Released Annually (J)

3.8E+18 5.7E+17 2.0E+17 6.8E+16 1.5E+16 4.5E+15 1.4E+15 4.5E+14 1.4E+14

4.6E+18 Minimum Power (W)

2.7E+09 8.1E+08 2.9E+08 9.7E+07 2.1E+07 6.3E+06 2.0E+06 6.3E+05 2.8E+05

3.9E+09 Maximum Power (W)

1.2E+11 1.8E+10 6.5E+09 2.2E+09 4.7E+08 1.4E+08 4.5E+07 1.4E+07 4.5E+06

1.5E+11

Energy Released by single events

• Earthquakes are not sustained events, so energy is not released uniformly • Japan’s 9.0 magnitude earthquake on March 11, 2011 lasted approximately 6 minutes • This means that over the period of 180 seconds, 1.1 x 10^16 Watts of energy were released