When Regional becomes Local: Linking Regional Seismicity to Perturbations at the Boiling Lake, Dominica

Abstract:

Dominica is one of 11 volcanically active islands located along the Eastern Caribbean arc. The Boiling Lake-Valley of Desolation area is part of a volcano-hydrothermal system on the island and was identified as the most likely location for a future eruption (Lindsay et. al, 2005). The last phreatic eruption on the island took place within the Boiling Lake-Valley of Desolation area in 1997. In addition to these eruptions the Boiling Lake has undergone six brief periods of physical and chemical instabilities during its 150 years of recorded history. The latest period occurred in 2004-2005 when the Boiling Lake experienced erratic disruptions in geothermal activity. It repeatedly emptied and refilled before returning to its long term stable state. Given such long term stability, a significant, but historically infrequent, perturbation is required to upset the Lake’s dynamic equilibrium. Prior to 2004-2005, the factor(s) triggering the instabilities have not been identified.

The current work is part of a multi-scale approach at understanding volcano-hydrothermal systems from a geophysical perspective, which incorporates modeling and observed data.

Here, the author briefly introduces the multi-scale approach and then focuses on the role of regional earthquakes as possible triggers of the Lake’s disruptions. This is discussed in terms of seismic events, induced stress-fields, faults systems and hydrodynamic changes. Finally the author reports on a number of significant events which may define the long elusive perturbation affecting the Boiling Lake.