 |
| Titel |
Spatial distribution of non volcanic tremors offshore eastern Taiwan |
| VerfasserIn |
X.S Xie, J. Y. Lin, S. K. Hsu, C. H. Lee, C. W. Liang |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250058614
|
|
|
|
|
|
| Zusammenfassung |
| Non-volcanic tremor (NVT), originally identified in the subduction zone of the
southwest Japan, have been well studied in the circum-Pacific subduction zones and the
transform plate boundary in California. Most studies related NVT to the release of
fluids, while some others associated them with slow-slip events, and can be triggered
instantaneously by the surface waves of teleseismic events. Taiwan is located at a complex
intersection of the Philippines Sea Plate and the Eurasian Plate. East of Taiwan, the
Philippine Sea plate subducts northward beneath the Ryukyu arc. The major part
of the island results from the strong convergence between the two plates and the
convergent boundary is along the Longitudinal Valley. Moreover, an active strike-slip
fault along the Taitung Canyon was reported in the offshore eastern Taiwan. In
such complicate tectonic environments, NVT behavior could probably bring us
more information about the interaction of all the geological components in the
area.
In this study, we analyze the seismic signals recorded by the Ocean bottom Seismometer
(OBS) deployed offshore eastern Taiwan in September 2009. TAMS (Tremor Active Monitor
System) software was used to detect the presence of NVT. 200 tremor-like signals were
obtained from the 3 weeks recording period. We use the SSA (Source-Scanning
Algorithm) to map the possible distribution of the tremor. In total, 180 tremors were
located around the eastern offshore Taiwan. The tremors are mainly distributed in two
source areas: one is along the Taitung Canyon, and the other is sub-parallel to the
Ryukyu Trench, probably along the plate interface. Many tremors are located at
depth shallower than 5 km, which suggests a possible existence of a weak basal
detachment along the sea bottom. Other tremors with larger depth may be related to the
dehydration of the subducting sea plate as suggested by the former studies. Limited by the
short recording period of the OBS experiment, we could not obtain any possible
repeating interval and the spatial migration about the tremor occurrence. However,
the presence of NVT offshore eastern Taiwan shown in our study still brings us
valuable understanding about the undergoing tectonic processes in the marine area. |
|
|
|
|
|
|