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Energetic Onset of Earthquakes
Author(s) -
Denolle Marine A.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl080687
Subject(s) - seismology , geology , seismic moment , moment (physics) , magnitude (astronomy) , moment magnitude scale , broadband , energy (signal processing) , fault (geology) , physics , geometry , mathematics , classical mechanics , astronomy , scaling , optics , quantum mechanics
Earthquake radiation is broadband, and its temporal evolution carries the seismic signature of the rupture process. I use established and develop new observational metrics to quantify the temporal variation in radiated energy (seismic power) and in a time‐dependent scaled radiated energy. Universal functional forms of moment rate, seismic power, and scaled energy arise from a global database of source time functions. Earthquakes radiate mostly and most efficiently in the early stage of development of the rupture that is in the first 10–30% of the overall rupture duration. This result is independent of earthquake magnitude, depth, and focal mechanism. Beyond depth dependence in elastic properties with depth that explain variations in source duration and radiated energy, subtle differences in functional forms exist between shallow and deep earthquakes. Deep events have a slower development than shallow earthquakes, but they carry a higher peak in seismic power.