Open AccessThe Fracture Energy of Earthquakes
Author(s) -
Husseini Moujahed I.,
Jovanovich Dushan B.,
Randall M. J.,
Freund L. B.
Publication year - 1975
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1975.tb00640.x
Subject(s) - seismology , erg , seismic moment , geology , shear (geology) , fracture (geology) , fracture mechanics , radius , rigidity (electromagnetism) , fault (geology) , materials science , geotechnical engineering , composite material , physics , petrology , optics , retina , computer security , computer science
Summary The arrest of a semi‐infinite longitudinal shear crack is caused by either (1) the finiteness of available strain energy, or (2) an increase in fracture energy along the trajectory of the running crack. In the former case the following relationship may be used to evaluate the fracture energy:where γo is the fracture energy per unit length along the crack edge per unit extension of the cracktip (erg cm −2 ), R is the characteristic radius of the fault (cm), Δσ is the stress drop (dyne cm −2 ) and μ is the rigidity (dyne cm −2 ). This leads to the following relationship:or from the Keylis‐Borok relationship (1959):where M o is the seismic moment in dyne cm −1 . These two relationships are statistically acceptable for Southern California faults and the Tonga‐Kermadec Arc earthquakes. The fracture energy is found to vary from 10 3 to 10 9 erg cm −2 with fresh fracture being associated with 10 7 ‐10 9 erg cm −2 while frictional rupture with 10 3 ‐10 7 erg cm −2 . These values are in good agreement with other independent estimates.