*************************************** Lascar ongoing eruption - preliminary report *************************************** From: Jorge Clavero Ribes <jclavero@xxxxxxxxxxxxxx> Lascar volcano, located in the Central Andes of Northern Chile (23º22'/67º44'W) started an eruptive cycle on April 18th 2006 at 11:35 hrs (all are local times). Four explosions were recorded on the 18th, one rose up to 3,000 m above the active crater. Two explosive cycles were observed on the 19th starting at 11:20 hrs and 13:21 hrs, the second being the largest rising up to 800 m above the crater. The plume, which essentially consisted in gases with little ash, was dispersed towards the north. Fine ash fell on the northern upper flank of the volcano within a radius of 3 km. Two new explosive cycles were observed on April 20th starting at 11:05 and 13:39 hrs. The latter has been the longer observed so far, lasting 1 hour and 53 minutes. The plume consisted mainly of gases and little ash, rising up to 2500 m above the crater and dispersed towards the N at the beginning and at the end of the cycle towards the NE. Fine ash was deposited on the upper northern and eastern flanks. Finally two new, but smaller, explosive cycles were observed today starting at 08:48 hrs and 11:42 hrs, lasting less than 15 minutes each, with an eruptive column rising up to 3000 m above the crater, similar to those of the previous day, but dispersed towards the west and SW, respectively. These phreatic explosions show an unusual behavior of the volcano, and there is no evidence so far of new magma reaching the surface. Preliminary seismic data obtained by the Chilean Emergency Office (ONEMI) show only seismic events related to shallow degassing, without any seismic event associated to deeper fractures or magma movements. Jorge Clavero-Chilean Geological Survey (Sernageomin) Juan Cayupi-Chilean Emergency Office (ONEMI) ============================================================== 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. ==============================================================
