VOLCANIC AND OTHER NATURAL HAZARDS OF THE LAKE ATITLáN REGION, GUATEMALA

Volcanoes are closely positioned with respect to people, infrastructure and national treasures all over Central America. This example serves to illustrate the complexity of natural hazard work there.

The “jewel” of the Guatemalan Highlands is Lake Atitlán, which fills the Atitlán Caldera, the source of several Late Pleistocene eruptions including the VEI 8 Los Chocoyos event at 84 ka. This caldera is bounded by three volcanoes (Atitlán, Toliman and San Pedro) that postdate the caldera events and is also quite densely populated with indigenous Guatemalans and is a prime focus of Guatemala's growing tourist industry. The volcanoes are quite closely spaced and their hazards zones overlap. Although all of the volcanoes have been inactive for more than a century, only one of the three, Atitlán, has historic activity. Limited age dating (Haapala et al., USGS OFR 2005-1403) suggest that the three volcanoes may have distinct age relationships (from oldest to youngest: San Pedro, Toliman, Atitlán). The three volcanoes differ in chemistry and style of activity and present distinct potential hazards. In areas like Lake Atitlán and in Central America in general, more age dating is critically needed to clarify volcanic hazards and to focus hazard mitigation efforts. Volcano has been marked by dangerous explosive and pyroclastic flow activity in historic and prehistoric times which resembles nearby Fuego Volcano but its recent inactivity has resulted in increased agricultural occupation. In areas like Lake Atitlán and in Central America in general, more age dating is critically needed to clarify volcanic hazards and to focus hazard mitigation efforts.

Together with the caldera, the lake region is marked by steep and unstable slopes. In addition to volcanic hazards, the region has significant potential for earthquake, hurricane, landslide and tsunami hazard. Landslide hazards associated with hurricanes have been very prominent in recent years. Overall the Lake region is an important focus for hazard mitigation effort, and presents a very wide variety of natural hazards and a unique social context and vulnerability.