Predicting the block-and-ash flow inundation areas at Volcan de Colima (Colima, Mexico) based on the present day (February 2010) status

摘要

Maps of areas potentially affected by block-and-ash flows and associated ash clouds are here presented for the Volcan de Colima. TITAN2D 2.0.1 code has been used to simulate block-and-ash flows using as an input volume that of the actual summit dome (assessed at 2 × 10~6 m~3), while the Energy Cone model has been used to delimit the possible inundated area from associated ash clouds. Both Merapi- and Soufriere-type block-and-ash flows were generated using different basal friction angles and maintaining fixed the volume and the internal friction angle. The setting of the input parameters takes into account some flow characteristics, such as the stepwise aggradation of different pulses that piled up to form the total thickness of the block-and-ash flow deposits. The outputs of the computational routines are reported as two maps describing the total thickness of the final deposits. They predict that thick deposits will engulf the ravines descending from the main cone to the west, south and southeast, with expected maximum runouts between 4.5 and 7 km. The associated ash clouds have slightly longer runouts, and the model predicts they will inundate some higher grounds that are not affected by the concentrate underflows. The presented maps represent useful tools for managing the current block-and-ash flow hazard at Volcan de Colima.