A repeating event sequence alarm for monitoring volcanoes

A major challenge in volcanology is forecasting eruptions. Repeating earthquake sequences may precede volcanic eruptions or lava dome growth and collapse, providing an opportunity for short-term eruption forecasting. I develop an automated repeating earthquake sequence detector and near real-time alarm to send alerts when an in-progress sequence is identified. The algorithm is based on a standard event detector (e.g., STA/LTA) and subsequent correlation-matching procedure that identifies repeating event sequences. A notification algorithm determines when a sequence is in progress and sends alerts. I use eruptions of three Alaskan volcanoes as case studies to test the alarm, implementing it both in retrospect and in real-time during the 2016-2017 Bogoslof eruption. These case studies show that the alarm can successfully be used to detect and alert on sequences of repeating events in a timely manner.