*************************************************************** From: Eliecer Duarte <eduarte@xxxxxxxxx> *************************************************************** Observatorio Vulcanológico y Sismológico de Costa Rica. OVSICORI-UNA Press Bulletin (June 06, 2008) Incandescent avalanche triggered by lava flow collapse. On Friday 06, June 2008 at 9:15am (15:15GMT) a hot avalanche rolled down the SW slopes of Arenal volcano, Costa Rica. An unestimated amount of blocky, andesitic lava was accumulating, on the summit, since March 2007 due to the extrusion of a lava flow. Even though fragments of such lava flow fell intermittently over these 14 months, it was until now that a mayor avalanche took place. Two minor ones were reported in recent months. The present collapse provoked a scar of some 800m long from the summit to the bottom. Lose, dry, incandescent material was canalized down the slope conforming a wide chaotic fan, at aprox 900m asl. Material rolling down pulverized and generated a tall plume of gases and dust that provoked panic in tourists and park rangers located some 2 kms. away, on the W side. Immediately the park was closed for the day and the tourists rapidly evacuated. No one was hurt. Dust and fine ashes deposited in a small area W and NW of the active flank. Rain rapidly diluted the fine film that was deposited on vegetation. Sampling and measurements of the affected area was postponed for the next few days for safety reasons. It is believed that within the next few days the active lava flow may occupy the channel as it happened in several similar events observed in the past. Finally, the affected sector does not offer a threat to visitors, park rangers or residents. On the contrary it is located in a safe remote sector of the volcano. Original bulletin (English and Spanish) can be found at. http://www.ovsicori.una.ac.cr/informes_prensa/2008/BoletinVAre6608pd.pdf ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
