Chile
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Dr Jennie Gilbert and Dr Steve Lane were involved in an expedition to Volcán Sollipulli, Chile in 1993 with scientists from the University of Bristol and the Servicio Nacional de Geologia y Mineria, Chile. This currently dormant volcano is situated in a relatively populated part of southern Chile, between the active volcanoes Llaima and Villarrica. The aim of the expedition was to assess the hazards associated with an eruption at Volcán Sollipulli. Ground penetrating radar and gravity surveys were carried out within the ice-filled caldera and these data have shown that the caldera attains a depth of up to 650 m in its central part and contains a minimum ice volume of 6 km3 (Gilbert et al. 1996). The geological work carried out during the expedition demonstrated that post-caldera collapse products were erupted almost exclusively along the caldera margins in the presence of a large body of intra-caldera ice. The Alpehué crater in the southwest part of the caldera was formed by an explosive eruption between 2960 and 2780 years B.P., This post dated caldera collapse. Such post-caldera eruptions have resulted in an increase in height of the walls and concomitant deepening of the caldera with time.
Aerial view of Sollipulli summit calderaThis image shows the ice-filled caldera of Volcán Sollipulli. North is upwards and parallel to the edge of the photograph. The field of view from east to west is 10 km. The caldera has an average diameter of 4 km and an ice-filled crater (Alpehué crater) 1 km in diameter on the southwest rim. |
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Northern rim of the calderaThe photograph shows the south facing caldera wall ~100 m of which is exposed above the level of the ice within the caldera. Since only a reconnaissance geological study has been made here the precise nature and significance of these deposits is as yet unknown. |
Ice pit on northern rim of calderaThe photograph shows Dr Jennie Gilbert and Dr Clare Adam carrying out a topographic survey of the snow/ice surface within Sollipulli's caldera. This image provides an impression of the huge volume of ice available for melting during an eruption. Because most rivers on the flanks of the volcano lead to the town of Melipeuco, this town is at risk from flooding in the event of an eruption. Photograph by S. J. Lane. |
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Nevados de Chillan
A little known volcanoDr Jennie Gilbert has recently been involved with an ODA/British Geological Survey project studying the geology, geochemistry, historical activity and volcanic hazards of Volcán Nevados de Chillán. Volcán Nevados de Chillán is an active volcanic complex comprising two edifices which cover an area of approximately 150km². These are the Cerro Blanco Complex in the north (seen in this photograph) and the Las Termas Complex in the south. The volcano has had several vents active in the last 60ka. Photograph by J. S. Gilbert. |  |
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Intriguing jointing patternsColumnar jointed lava in Aguas Calientes region of Nevados de Chillán. Photograph by J. S. Gilbert. |
Surveying the calderaDr Jennie Gilbert carrying out a levelling survey within the ice-filled caldera of Volcán Sollipulli. Photograph by S. J. Lane. |  |
It certainly looks like a volcano!Volcán Llaima photographed from Volcán Sollipulli in February 1993. Photograph by J. S. Gilbert. |  |