Premium
Elevation changes and the Great 1960 Chilean Earthquake: Support for aseismic slip
Author(s) -
Linde Alan T.,
Silver Paul G.
Publication year - 1989
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/gl016i011p01305
Subject(s) - geology , slip (aerodynamics) , seismology , seismic moment , trench , geodesy , episodic tremor and slip , oscillation (cell signaling) , subduction , fault (geology) , tectonics , physics , chemistry , genetics , organic chemistry , layer (electronics) , biology , thermodynamics
We reanalyse the near‐field vertical displacement data for the great Chilean earthquake of 1960 to provide constraints on the down‐dip slip distribution. A recent study of free oscillation data confirms earlier proposals of a slow precursor comparable in size to the main shock; we seek evidence for this event in the displacement data. Spatial coverage of the data is inadequate to allow determination of a unique fault model, but inversions show that thrust slip must extend over a width of about 300 km and to a depth between 60 km and 85 km, well below the seismogenic zone for interplate events. We propose that this deeper slip is the source of the slow event. Our preferred class of solutions has moments ranging from 1.6 × 10 23 N m to 2.5 × 10 23 N m, only 30% to 45% of the free oscillation value. Underestimation of the near trench displacements by 50% together with a seismic overestimation of moment by 30% due to tradeoff with rise time would result in satisfactory agreement.