Date: Mon, 19 Sep 1994 13:55:06 MST Reply-To: VOLCANO
Sender: VOLCANO Comments: Converted from OV/VM to RFC822 format by PUMP V2.2X From: Global Volcanism Network Subject: Aug 94 Rabaul Volc Obs report To: Multiple recipients of list VOLCANO Status: OR ----------------------------Original message---------------------------- SMITHSONIAN INSTITUTION - GLOBAL VOLCANISM NETWORK. Report of August 1994 activity at Rabaul from the Rabaul Volcano Observatory. Rabaul New Britain, Papua New Guinea (4.27xS, 152.20xE) The following report was received from the Rabaul Volcano Observatory on 9 September 1994. "Until the 24th, August was almost as quiet as the preceding two months. Between 25 and 28 August, 227 earthquakes were detected with more than half of them on the 26th. Unusually for Rabaul, these earthquakes tended to be discrete events; there was very little swarming. It was quiet again after 29 August, and the total number of detected events for the month was 448, compared to 220 in both June and July (see Bulletin v. 19, no. 7). "Caldera earthquakes located in August totaled 34, 25 of them during 25-28 August. Most of the earthquakes were located on the ring fault near Tavurvur, or offshore to the S and SW; 17 located hypocentres had location errors of <1 km. None of the earthquakes were felt, the largest event, on 26 August, was ML 2.6. "On 28 August, the caldera network recorded what appeared to be a low-frequency earthquake. Signals with a dominant frequency of ~1 Hz were recorded, but only on some of the inner network stations. The signals were very complicated with no clear phase arrivals and no clear onsets. The origin of these signals was probably closest to the seismometer on Matupuit Island." Information Contacts: I. Itikarai, R. Stewart, and C. McKee, Rabaul Volcano Observatory, P.O. Box 386, Rabaul, Papua New Guinea.