 |
| Titel |
Investigating volcanic hazard in Cape Verde Islands through geophysical monitoring: network description and first results |
| VerfasserIn |
B. Faria, J. F. B. D. Fonseca |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1561-8633
|
| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Sciences ; 14, no. 2 ; Nr. 14, no. 2 (2014-02-28), S.485-499 |
| Datensatznummer |
250118288
|
| Publikation (Nr.) |
 copernicus.org/nhess-14-485-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| We describe a new geophysical network deployed in the Cape Verde Archipelago
for the assessment and monitoring of volcanic hazards as well as the first
results from the network. Across the archipelago, the ages of volcanic
activity range from ca. 20 Ma to present. In general, older islands are in
the east and younger ones are in the west, but there is no clear age
progression of eruptive activity as widely separated islands have erupted
contemporaneously on geological timescales. The overall magmatic rate is low,
and there are indications that eruptive activity is episodic, with intervals
between episodes of intense activity ranging from 1 to 4 Ma. Although only
Fogo Island has experienced eruptions (mainly effusive) in the historic
period (last 550 yr), Brava and Santo Antão have experienced numerous
geologically recent eruptions, including violent explosive eruptions, and
show felt seismic activity and geothermal activity. Evidence for recent
volcanism in the other islands is more limited and the emphasis has therefore
been on monitoring of the three critical islands of Fogo, Brava and Santo
Antão, where volcanic hazard levels are highest. Geophysical monitoring of
all three islands is now in operation. The first results show that on Fogo,
the seismic activity is dominated by hydrothermal events and volcano-tectonic
events that may be related to settling of the edifice after the 1995
eruption; in Brava by volcano-tectonic events (mostly offshore), and in Santo
Antão by volcano-tectonic events, medium-frequency events and harmonic
tremor. Both in Brava and in Santo Antão, the recorded seismicity
indicates that relatively shallow magmatic systems are present and causing
deformation of the edifices that may include episodes of dike intrusion. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|