Re-assessing volcanic hazard zonation of Volcán de Colima, México

Volcán de Colima is one of the most active volcanoes in Mexico. Several hazard maps have been published based on reconstruction of the Late Pleistocene–Holocene eruptive history and historical records for the last 400 years. Recent detailed published studies have improved the knowledge of the eruptive history of the volcano and proposed a new hazard zonation based on numerical simulation for debris avalanche, pyroclastic density currents (PDCs), debris flows and fallout events. The new hazard map incorporates all these new data and proposes a revised hazard zonation useful for improving decision-making both previously and during crises. A sub-Plinian to Plinian multi-stage eruption similar to the ad 1913 event would represent a major hazard for populated areas around Volcán de Colima. PDCs initiated by column collapses could travel up to 15 km from the eruptive vent. Tephra dispersal modeling shows that up to 10 cm of fallout deposits could affect several cities (population more than~180,000 people). Lahars (including the wide spectra of volcaniclastic flows), the most common hazard during the rainy season, would affect the main ravines up to a distance of 15 km from the Volcán de Colima cone, impacting infrastructures and small villages. A Plinian eruption scenario also includes the possible generation of large volume lahars (up to 5 × 106 m3), possibly reaching major villages (i.e., San Marcos, Quesería, Tonila) with catastrophic effects. Block-and-ash PDCs from summit dome collapse will travel in the main ravines up to distances between 4 and 7 km, with slightly longer runout for associated turbulent PDCs. Despite a recurrence rate probably >2,000 years, partial edifice collapse constitutes the major hazard. Large volume (>5 km3) debris avalanches can disrupt the southern slopes of the volcano up to a distance of 30 km affecting the Colima city, potentially associated with laterally directed blasts and secondary debris flows that in the past reached the Pacific coast