Computer simulations of lava flow paths in the town of Goma, Nyiragongo volcano, Democratic Republic of Congo

摘要

The 17 January 2002 fissure eruption of Mount Nyiragongo, Democratic Republic of Congo, produced lava flows which entered and devastated the densely inhabited town of Goma. The 2002 and previous 1977 eruptions demonstrate the high level of volcanic risk in the area. We present an analysis of the susceptibility to lava flow invasion in Goma, by means of computer simulations based on the steepest descent path and probabilistic-computed flow spreading and obstacle overcoming. The DEM is obtained from a topographic map of Goma by using the DEST algorithm. The numerical results show the distribution of probable lava flow paths from possible vents in the investigated topographic domain. Numerical simulations are validated through comparison with the mapped paths of the 2002 lava flows in Goma. The subsequent investigation includes the analysis of (1) hypothetical lava flow paths from ephemeral vents on the edge of the 2002 lava flows, (2) paths from venting along the hypothetical extension of the 2002 fissures, (3) paths in case of lava flow arrival in town from the north, and (4) changes induced by the presence of the solidified 2002 lava field. The results show the susceptibility of the different parts of the town of Goma to be invaded by future lava flows, and reveal the existence of a large area in town with minimum susceptibility and which can be invaded only in case of venting within it. The areas destroyed by the 2002 lava flows are predicted to be characterized by maximum susceptibility to lava flow invasion.