Mapping and Assessment of Volcanic Hazards Related to the IgnimbriticEruption by AMS in Bambouto Volcano (Cameroon Volcanic Line)

摘要

Pyroclastic deposits constitute major components of explosive volcanic activity. To help improve the safety ofthe population faced with natural disasters, a study is carried out at Bambouto volcano with a view to map potentialhazards related to pyroclastic flows. The Bambouto volcano is indeed considered to be still active since the recentdiscovery of Quaternary basalts (0.5 Ma) at Totap, a locality situated near the Bambouto Caldera. This discovery has ledto reclassify Mount Bambouto among active volcanoes of Cameroon and, therefore, considered as potentially dangerous.The dangerousness of this volcano is accentuated by the presence of ignimbrites that are witnesses of ancient pyroclasticflows. Because a map of volcanic hazards is non-existent on the volcano, anisotropy of magnetic susceptibility (AMS) isthe method used in this paper to characterize magnetic fabrics and provides an estimate of flow direction of eachignimbrite sheet (represented by massive lapilli tuff and massive lithic breccia facies). Inferred transport directions basedon the AMS data and field indicators show that Bambouto Caldera is the source of main pyroclastic deposits of MountBambouto. These results have enabled us to produce a new hazard map related to potential future pyroclastic flows.