Pacaya Southern Guatemala 14.38 N, 90.60 W; summit elev. 2,552 m All times are local (= GMT - 6 hours) Pacaya erupted more forcefully than usual beginning late on 10 October. Based on an INSIVUMEH report, between about 2300 on 10 October and 0200 on 11 October Pacaya produced a moderate Strombolian eruption with sustained fountaining of incandescent materials up to 500 m high. The plume's maximum height reached ~3.7 km altitude; within that plume the ash column rose to ~700 m. During the eruption winds blew from the NNE at 35 km/hour with gusts to 45 km/hour; they carried fine ash toward the town of Esquintla. A report from Puerto San Jose, a city on the Pacific coast ~60 km SW, indicated that the earlier dark ash cloud had thinned during the day. The explosive eruption was followed by significant lava effusion from the crater. The longest lava flow travelled SW for 1.5 km over the surface of an older flow field. At 0300 the flow front's velocity was 100 m/hour; it came within 300 m of the relatively flat area reached by the 1991 lava flow. Lava ceased venting at dawn; however, the SW flow remained incandescent and slowly moving. Although eruptive strength diminished, some tremor persisted on 11 October. On that day satellite images (Band 2 on GOES-8) showed a small hot spot. An INSIVUMEH report on 14 October noted that ongoing eruptions continued into the morning of the 12th. After that the eruptive vigor and amount of tremor both dropped and no new lava vented from the crater. On 16 October INSIVUMEH reported that Pacaya continued to expel abundant white steam. At that time there were no audible explosions, underground booming noises, or newly vented lava flows. Tremor was present, presumably related to the degassing seen at the surface. Eddy Sanchez noted that 38 people were evacuated from neighboring villages during the height of the eruption. The last reported activity at Pacaya (Bulletin v. 20, no. 5) consisted of an eruption on 1 June 1995 that generated a 6-km-high plume, produced ashfall a few kilometers away, and emitted lava. Pacaya sits 30 km S of the center of Guatemala City, an urban center with a population of >1.5 million. A 1989 eruption produced a 4.5-km-tall eruption column and enlarged the MacKenney crater. Lava flows followed in 1990-91. Strong eruptive activity in June- August 1991 destroyed part of the MacKenney cone and damaged villages to the W. Lavas have often flowed out of the collapsed SSW sector, traveling away from most inhabited areas. The international airport (La Aurora) lies ~23 km from the crater and airplanes commonly fly over the volcano. Information Contacts: Eddy Sanchez and Otoniel Matias, Seccion Vulcanologia, INSIVUMEH (Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hydrologia of the Ministerio de Communicaciones, Transporte y Obras Publicas), 7A Avenida 14-57, Zona 13, Guatemala City, Guatemala; NOAA/NESDIS Satellite Analysis Branch, Room 401, 5200 Auth Rd., Camp Springs, MD 20746 USA.