Field observations of the 2008 summit eruption at Piton de la Fournaise (Ile de La Réunion) and implications for the 2007 Dolomieu collapse

More than one year after the most important eruption ever observed at Piton de la Fournaise in April 2007, a new eruption started in 2008 at Piton de la Fournaise, with three different eruptive phases in September, November and December. They were located within the 340 m deep Dolomieu crater. Due to the steep (dip angle 45–80°) and unstable walls of the new crater formed in April 5, 2007, no measurements in situ of the 2008 eruption had been possible. Only observations from the Dolomieu crater rim and from helicopter were performed, using an infrared camera, a portable rangefinder and numerous photographs. These field observations allowed precise monitoring of the setting up of the lava flows with time. The total erupted volume of lava of the three phases was 2.2 × 106 m3 and the average flow rates ranged between 0.3 and 1 m3 s− 1. Lava temperatures of up to 1150 °C have been measured by an infrared camera. Overall, infrared images of the Dolomieu crater illustrate the control of the eruptive vents by the structure of the April 2007 Dolomieu collapse.