[IGSSTATION-8926] Displacement of IGS site ADIS due to volcanic intrusion

[Freymueller, Jeffrey]

I’m sending this message to alert the whole IGS community about the physical cause of this event, and to point you to additional information – keep watching the COMET site for more news.

Since late December, there has been a significant westward displacement of the IGS site ADIS, approaching ~20 mm so far, which is caused by a large volcanic intrusion that is more than 100 km distant. The westward displacement appears to be detectable by around 20 December, but became much larger around 24 December. This corresponds to a rapid lengthening of the dike intrusion, which has now reached about 50 km in length and extends between Fentale and Dofen volcanoes. Data for this mostly comes from InSAR, and you can see some beautiful interferograms in the reports at the link below.

Juliet Biggs at the University of Bristol noted
“We've been putting together a series of event response reports through the crisis, which you might be interested in: https://comet.nerc.ac.uk/publications/event-response-reports/<https://urldefense.com/v3/__https:/comet.nerc.ac.uk/publications/event-response-reports/__;!!HXCxUKc!1DfNSwpw4jrkCuJ3AHfblo65zB5fEVXNHEQ9PWzYkUq_C38vVEYZ9-ylbtEASlIPxNQjTNVaVurH8TPdPyAG7toQFuE$>. The intrusion seems to have ended for now, but we never know if there will be another phase.”

The larger displacement corresponds to a particular phase in the event, which they describe in their January 14th report, and show in Figure 2f,g of that report.

“Between 24th and 29th December, there was a change in direction, accompanied by an acceleration in dyke propagation. The dyke tip propagated about 24 km in 5 days (Fig 2f,g) and reached the neighbouring volcano Dofen, 47 km to the north of Fentale. The direction of the dyke changes from radial to Fentale to aligned with the rift axis (~020°). LOS deformation associated with dyke opening is ~36 cm.”

Jeff
--------------
Dr. Jeffrey T. Freymueller
Endowed Chair for Geology of the Solid Earth
Department Chair
Dept. of Earth and Environmental Sciences
Michigan State University
URL:  https://msu.edu/~freymuel/



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