loading page

Clog and Crack: Opening and Closing Behavior During a Sustained Explosive Eruption as recorded by its Hidden Earthquakes
  • +1
  • Ricardo Garza Giron,
  • Emily E Brodsky,
  • Zack Jack Spica,
  • Matthew M Haney
Ricardo Garza Giron
University of California, Santa Cruz

Corresponding Author:rgarzagi@ucsc.edu

Author Profile
Emily E Brodsky
University of California, Santa Cruz
Author Profile
Zack Jack Spica
University of Michigan
Author Profile
Matthew M Haney
United States Geological Survey
Author Profile


Volcanic eruptions progress by co-evolving fluid and solid systems. The fluid mechanics can be observed through the plumes and ejecta produced, but how does the solid system evolve? When does the conduit open? When does it close? Seismology can potentially tell us about these processes by measuring the failure of the solid rock. Such inferences require the detection of earthquakes during an explosive eruption. Standard earthquake detection methods often fail during this time as the eruption itself produces seismic waves that obscures the earthquake signals. We address this problem by applying supervised and unsupervised search techniques to the existing catalog of the 2008 Okmok eruption to find brittle failure signals during the continuous eruptive sequence. The interaction between fluid pathways and seismicity is reinforced by high precision earthquake relocations that highlight a ring-fault structure, which may be acting as a conduit for fluids to the surface. The timing of the earthquakes during the eruption reveal that the seismicity gradually increases during the vent-opening stage (July 12-July 24), peaks during the vent-widening stage (July 24-August 1) which culminates in a large burst of earthquakes, and then gradually decrease until the end of the eruptive period. Seismic bursts during the eruption are not synchronized with the exhalation of large ash and steam plumes. In other words, when the system is closed, the rock breaks. We call this scenario clog and crack.