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Ground‐coupled air waves and diffracted infrasound from the Arequipa earthquake of June 23, 2001
Author(s) -
Le Pichon A.,
Guilbert J.,
Vega A.,
Garcés M.,
Brachet N.
Publication year - 2002
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 - 10.1029/2002gl015052
Subject(s) - infrasound , seismology , geology , azimuth , microseism , physics , acoustics , astronomy
On June 23, 2001, a strong earthquake measuring M w 8.4 occurred along the coast of south‐central Peru. Coherent infrasonic waves were detected over a period of one hour by the IS08 infrasound station in Bolivia. Analysis of the ground‐coupled air waves shows that the rupture propagated from the northwestern to the southeastern part of the fault with a rupture velocity of 3.3 km/s. The azimuth variation of the infrasonic waves is attributed to a distribution of secondary sources along the highest mountain ranges, which excite infrasonic waves that are diffracted to the ground. The predominant source of infrasound is likely distributed along the Andean Cordillera. Using the azimuth and arrival time determination, the horizontal scale size of the distant source regions of infrasonic waves is reconstructed over distances greater than 400 km.