Aeolian Islands, Italy (38.79 N, 15.21 E)

(This report is relative to the period 11.06 - 15.09.1995)

The tremor intensity showed little changes between 10 June and 11 August. The only significant variations of the reporting interval are found between 12 August and 27 August, when a slow increase of the tremor intensity was observed, and in the following four days, which were characterized by a rapid return of the intensity to the previous range of values, observed throughout the first fortnight of September.

Noteworthy is the lack of a great number of saturating events, as opposed to the period between March and May 1995, i.e. the period including the significant 5 March explosion (see Bullettin, v. 20, n. 4 & 5). This means that the Strombolian explosive activity was either less energetic or shallower, i.e with more energy released towards the air than into seismic waves.

The total number of recorded events showed a rise and subsequent decrease during the period mid June - mid July, with two minima of 50-60 events per day and a maximum of almost 200 events per day recorded on 26 June. Another rise followed starting mid-July, reaching values of 260-280 events on 28 August and 3 September, in correspondance of the significant tremor decrease described above.

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Fig. caption:

open bars = number of recorded events per day

solid bars = saturating events, i.e. with ground velocity exceeding 100 µm/s

line = daily average of tremor intensity on hourly 60-seconds samples.