************************************************ Láscar April-August 2006 eruptive cycle update ************************************************ From: Jorge Clavero Ribes <jclavero@xxxxxxxxxxxxx> Lascar volcano, located in the Central Andes of Northern Chile (23º22'/67º44'W) started a new eruptive cycle on April 18th 2006, after almost one year of apparent repose (last eruption recorded in May 4th 2005) . After one week with several phreatic explosive cycles per day (some lasting up to two hours), reaching up to 3,500 m above the crater, the activity decreased. The ash collected in June around the crater area showed no signs of new magma, in agreement with seismic data (three seismometers were installed for one week, and one for nearly one month to record the seismic activity associated to the explosions). The volcano has continued its activity with several smaller explosions during May, July and August, although much more separated in time (up to several weeks). The last observed explosions occurred on June 12th at 16:00 hrs and August 14th at 18:00 hrs (local time, GMT-4)). The latter lasted for 5 minutes and the plume reached up to 450 m above the crater, and was rapidly dispersed towards the East-Southeast. This unusual long-lasting cycle of phreatic vulcanian explosions of Láscar volcano seems to continue, and efforts from the Chilean Geological Survey (Sernageomin) and the Chilean Emergency Office (Onemi) are under way to install permanent seismometers in the area. Although no signs of new magma have been recognised so far, ascent of new magma in the future cannot be ruled out. Jorge Clavero, José A. Naranjo (Chilean Geological Survey) Juan Cayupi (Chilean Emergency Office) ************************************************** Jorge Clavero R. Programa Riesgo Volcánico de Chile/Volcano Hazard Prog. Servicio Nacional de Geología y Minería Av. Santa María 0104-Providencia-Santiago CHILE F: 56-2-7375050 Fax:56-2-7379253 ************************************************** ============================================================== 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. ==============================================================
