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Infrasonic waves and volcanic tremor at Stromboli
Language
English
Obiettivo Specifico
5V. Sorveglianza vulcanica ed emergenze
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
2/23(1996)
Pages (printed)
181-184
Issued date
January 15, 1996
Abstract
The origin of the volcanic tremor is still under debate. Many theories have been proposed in the last years, but none has yet been completely accepted. In 1993, highly sensitive pressure sensors (2.175 Pa/Volt) used to monitor the explosive activity have revealed unexpected correlation between small spike-shaped pressure signals (1-2 Pa) and volcanic tremor. These pressure pulses repeat regularly in time with a recurrent period of ca. 1s. Video camera images allowed us to correlate the pressure pulses with small gas bursts occurring at one of the active vents. The striking correlation (0.971) between infrasonic and seismic energy fluctuations is particularly meaningful in the frequency domain. Infrasonic and seismic signals share the same spectral content (3Hz) for every station within a range of 700 m around the craters. Correlations in time and frequency domain remained unaltered during the 1994 field experiments. Moreover, during 1994, the increased degassing activity has been followed by an increase in pressure release (7-8 Pa) and by a shift towards higher frequencies (8Hz) both in the infrasonic and seismic records. Infrasonic waves and volcanic tremor show similar energy fluctuations and frequency contents, appearing therefore produced by the same dynamical process. On this basis we claim the volcanic tremor at Stromboli originates by continuous outbursting of small gas bubbles in the upper part of the magmatic column.
Type
article
File(s)
No Thumbnail Available
Name
95GL03662.pdf
Size
1.26 MB
Format
Adobe PDF
Checksum (MD5)
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