************************************************************************************** Activity on Piton de la Fournaise volcano on Reunion Island: From: Guillaume LEVIEUX <levieux@xxxxxxxxxxxxxxx> ************************************************************************************** Piton de la Fournaise volcano on Reunion Island: a short-lived eruption lasting 12 hours started on November 5, 2009 at 8:50pm (GMT +4). During the last 4 weeks, the OVPF (IPGP) Observatory recorded several seismic swarms located at about 2.6 km beneath the summit of Piton de la Fournaise volcano. The seismic activity was associated with a progressive inflation of the edifice. On October 18th, a first phase of tremor and magma ascent towards the surface was detected. This activity resulted in magma intrusion, inflation of the southern rim of the Dolomieu summit crater and formation of a new fumarolic field on the southern Dolomieu cliff. On November 5, an intense seismic swarm occurred between 7:30pm and 8:30pm (GMT +4) at about sea level, including an earthquake of 80 seconds. This crisis was followed by a 30 minutes aseismic phase and then by sustained tremor. The first vent opened at 8:50pm on the southern cliff inside the Dolomieu crater. At 9:05pm, a fracture propagated towards east on the upper south-eastern flank of Piton de la Fournaise feeding a first lava flow. A 9:20pm, a second fracture opened on the eastern volcano flank between 2450 and 2300m asl. The eruption was also recorded by the three webcams of the observatory, which, together with the deformation and tremor patterns, allowed a rapid identification of the eruption sites. The fractures fed strombolian activity, small (about 20 meters high) fountains and aa lava flows, which were visible from the national road lining the coast in the Grand Brûlé area. At 3:00am on November 6, the eruptive tremor declined to a very low intensity level. A first survey on the volcano summit at 7:30am confirmed that the lava fontaining was no longer active and the lava front had stopped at about 1900 m elevation. At 9:00am the eruptive tremor disappeared, thus confirming the end of the eruption. ============================================================== 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. ==============================================================
