Tornillo seismic events at Galeras volcano, Colombia: a summary and new information from broadband three-component measurements
| Autor: | null D. M. Gómez M., null R. A. Torres C., null D. Seidl, null M. Hellweg, null H. Rademacher |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1999 |
| Předmět: |
Seismometer
geography broadband record geography.geographical_feature_category tornillos Andesite lcsh:QC801-809 Dominant frequency volcanoes lcsh:QC851-999 Coda seismic events Travel time lcsh:Geophysics. Cosmic physics Geophysics Volcano Galeras volcano Broadband lcsh:Meteorology. Climatology Seismogram Geology Seismology |
| Zdroj: | Annals of Geophysics, Vol 42, Iss 3 (1999) |
| ISSN: | 1593-5213 1992-1993 |
| Popis: | Long-duration events have been recorded at several active, andesitic volcanoes. Their main characteristics are a single, sharp frequency peak, and an exceptionally long coda. Because their seismograms resemble a screw, these signals are called "tornillos" in Colombia. These events have been recorded during different stages of volcanic activity at various volcanoes worldwide. Tornillos have occurred for example, as a short-term precursor to eruptions at Galeras volcano, Colombia (1992-1993); and at Asama volcano, Japan, (1983). At Tokachi volcano, Japan, they were recorded after an eruption (1989). The Tornillo's dominant frequency appears to be related to the time of occurrence during an eruption cycle. It is independent of epicentral distance, azimuth, travel time, and lapse time, indicating that it is a source characteristic. Damping coefficients for the tornillo's coda range between 0.002 and 0.02. In contrast, damping coefficients for normal long-period events lies between 0.010 and 0.025 and for volcano-tectonic events between 0.010 and 0.040. In March 1996, the Galeras seismic network, which consists of short period, single-component seismometers, was augmented with a broadband, three-component station. This station, installed 1.5 km south of Galeras active cone, recorded a series of six tornillos. Narrowband and broadband tornillo records have similar characteristics in the time and frequency domains. |
| Databáze: | OpenAIRE |
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