Dynamic earthquake triggering response tracks evolving unrest at Sierra Negra volcano, Galápagos Islands

Area of Science:

• Geophysics
• Volcanology
• Seismology

Background:

• Dynamic earthquake triggering is influenced by local stress and perturbation amplitude.
• This dependency has not been previously confirmed within a single crustal volume.

Purpose of the Study:

• To investigate the relationship between stress state and dynamic earthquake triggering at Sierra Negra volcano.
• To determine how magma reservoir inflation and deflation affect seismicity.

Main Methods:

• Analysis of seismicity data from Sierra Negra volcano.
• Correlation of earthquake triggering intensity with volcanic deformation (inflation/subsidence) and dynamic strain from teleseismic surface waves.

Main Results:

• Dynamically triggered earthquake intensity increased with magma reservoir inflation and elevated stress.
• Increased peak dynamic strain amplified seismicity perturbations.
• Coeruptive subsidence and stress reduction led to a cessation of detectable dynamic triggering.

Conclusions:

• Local stress state and dynamic strain amplitude are primary controls on dynamic earthquake triggering.
• The response to dynamic stresses can help monitor and understand the evolution of volcanic unrest.