Rupture process of the 1995 Antofagasta subduction earthquake (Mw = 8.1)
Carlo, D.L.; Lay, T.; Ammon, C.J.; Zhang, J. (1999). Rupture process of the 1995 Antofagasta subduction earthquake (Mw = 8.1), in: Sauber, J. et al. Seismogenic and tsunamigenic processes in shallow subduction zones. Pure and Applied Geophysics, 154(3-4): pp. 677-708. https://dx.doi.org/10.1007/978-3-0348-8679-6_13
In: Sauber, J.; Dmowska, R. (Ed.) (1999). Seismogenic and tsunamigenic processes in shallow subduction zones. e-Book edition. Pure and Applied Geophysics, 154(3-4). Springer: Basel. ISBN 978-3-0348-8679-6. vi, 405-776 pp. https://dx.doi.org/10.1007/978-3-0348-8679-6, meer
In: Pure and Applied Geophysics. Birkhäuser: Basel. ISSN 0033-4553; e-ISSN 1420-9136, meer
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| Author keywords |
Finite-source rupture models Chilean tectonics seismic directivity |
| Auteurs | | Top |
- Carlo, D.L.
- Lay, T.
- Ammon, C.J.
- Zhang, J.
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| Abstract |
A finite-source rupture model of the July 30, 1995, M w = 8.1 Antofagasta (Northern Chile) subduction earthquake is developed using body and surface waves that span periods from 20 to 290 s. A long-period (150–290 s) surface-wave spectral inversion technique is applied to estimate the average finite-fault source properties. Deconvolutions of broadband body waves using theoretical Green’s functions, and deconvolutions of broadband fundamental mode surface waves using empirical Green’s functions provided by a large aftershock, yield effective source time functions containing periods from 20 to 200 s for many directivity parameters. The source time functions are used in an inverse radon transform to image a one-dimensional spatial model of the moment rate history. The event produced a predominantly unilateral southward rupture, yielding strong directivity effects on all seismic waves with periods less than a few hundred seconds. The aftershock information, spectral analysis, and moment rate distribution indicate a rupture length of 180-200 km, with the largest slip concentrated in the first 120 km, a rupture azimuth of 205° ± 10° along the Chilean coastline, and a rupture duration of 60–68 s with a corresponding average rupture velocity of 3.0–3.2 km/s. The overall rupture character is quite smooth, accentuating the directivity effects and reducing the shaking intensity, however there are three regions with enhanced moment rate distributed along the rupture zone: near the epicenter, 50 to 80 km south of the epicenter, and 110 to 140 km south of the epicenter. |
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