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The 1942 Southwest Indian Ocean Ridge Earthquake: Largest ever recorded on an oceanic transform
Author(s) -
Okal Emile A.,
Stein Seth
Publication year - 1987
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/gl014i002p00147
Subject(s) - seismology , geology , transform fault , ridge , seismic moment , slow earthquake , slip (aerodynamics) , directivity , indian ocean , scaling law , scaling , intraplate earthquake , fault (geology) , oceanography , tectonics , geometry , interplate earthquake , paleontology , telecommunications , physics , mathematics , computer science , antenna (radio) , thermodynamics
The 1942 Southwest Indian Ocean earthquake is the largest ever recorded on an oceanic transform. Its mechanism has essentially the expected pure strike‐slip geometry. Using long‐period surface wave techniques, the seismic moment is found to be 1.3 × 10 28 dyn‐cm; directivity suggests southwestward rupture propagation over approximately 130 km. This shock is then much smaller than previously reported on the basis of its high unified Richter magnitude ( M = 8.3). It does not show the slow energy release occasionally found in large transform fault events. Scaling laws and thermal modeling suggest that seismic slip extended at least to the 600° C isotherm.