HR: 09:00h
AN: S41B-04    [PDF]
TI: Co-Seismic Energy Changes Induced by Earthquakes on A Rotating, Gravitating Earth
AU: * Chao, B F
EM: benjamin.f.chao@nasa.gov
AF: Space Geodesy Branch, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Gross, R S
EM: Richard.Gross@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 United States
AB: Besides operating its own energy budget, an earthquake acts as an agent transferring a much greater amount of energy among the Earth's rotation, elastic field, gravitational field and internal heat. We compute the co-seismic, globally integrated gravitational and rotation changes induced by some 20,000 large earthquakes that occurred in the last quarter century, according to Chao et al. (1995, GJI, 122, 776- 783, 784-789) and using the Harvard CMT catalog. The result confirms an extremely strong tendency for the earthquakes to decrease the global gravitational energy and to increase the spin energy. It is found that energy is being extracted from the Earth's gravitational field by the action of earthquakes at an average rate of about ~2 TeraW during the studied period, larger by far than the ~7 GigaW for the average rate of the earthquake-induced rotational energy increase and the ~5 GigaW for the seismic energy release. Based on energetics considerations and assuming the inability of the Earth to build up elastic energy continuously over time, it is argued that earthquakes, by converting gravitational energy, may make a significant contribution to the global hear flow.
DE: 1239 Rotational variations
DE: 7209 Earthquake dynamics and mechanics
DE: 7230 Seismicity and seismotectonics
DE: 8123 Dynamics, seismotectonics
DE: 8130 Heat generation and transport
SC: Seismology [S]
MN: 2003 Fall Meeting