| Titre | GPS seismology: application to the 2002 Mw 7.9 Denali Fault Earthquake |
| |
| Auteur | Bilich, A; Cassidy, J F ; Larsen, K M |
| Source | Bulletin of the Seismological Society of America vol. 98, no. 2, 2008 p. 593-606, https://doi.org/10.1785/0120070096 |
| Image |  |
| Année | 2008 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20070150 |
| Éditeur | Seismological Society of America (SSA) |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1785/0120070096 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Région | Alaska; Denali |
| Lat/Long OENS | -148.0000 -144.0000 64.0000 63.0000 |
| Sujets | secousses séismiques; magnitudes des séismes; études séismiques; mécanismes de tremblement de terre; séismologie; données sismiques; Faille de Denali ; Tremblement de terre de Denali ;
géophysique |
| Illustrations | cartes de localisation; graphiques; tableaux; graphiques |
| Programme | Réduction des risques dus aux aléas naturels |
| Diffusé | 2008 04 01 |
| Résumé | (disponible en anglais seulement)
The 2002 Denali fault, Alaska, earthquake (Mw 7.9) caused one or more components of most broadband seismometers in western Canada to clip, yet did not trigger
strong-motion instruments, thus leaving a substantial gap in the seismic record of this event. However, the large-amplitude surface waves generated by this event were well recorded by the Global Positioning System (GPS) in the same region, out to
epicentral distances of more than 3000 km. In this article, we explore the capabilities of GPS seismology, specifically how the relative strengths of GPS and seismic data sets can be exploited in order to more effectively study earthquake source
characteristics and wave-propagation effects. High-rate (1-Hz) GPS data from 23 stations throughout western North America have been analyzed to derive displacement waveforms for this event, and the impact of instrumentation (GPS receiver model) and
errorreduction strategy (modified sidereal and spatial filtering) on the noise characteristics of displacement time series at each GPS site was assessed. After applying errorreduction methods to GPS displacements, the final average noise floors of
0.5 cm in the horizontal and 1.5 cm in the vertical indicate that large dynamic displacements are observable by GPS. We validate the GPS displacements by comparing broadband seismic recordings (integrated to displacement) with GPS recordings for four
effectively colocated sets of instruments. We show excellent agreement between the unclipped seismic and GPS recordings of the surface waves from the Denali earthquake over the period range of 10 - 50 sec and for ground displacements exceeding about
1.0 cm. Thus, a large GPS displacement data set is now available for western North America, an area where records of this event were previously missing or incomplete. The final GPS seismograms are archived at Incorporated Research Institutions for
Seismology (IRIS) for public use in future studies of the 2002 Denali earthquake. |
| GEOSCAN ID | 224065 |
|
|