CLEVELAND

Mount Cleveland—among the most active volcanoes in the United States this century (Cameron et al., 2018)—is an andesitic stratovolcano on the western half of Chuginadak Island that, along with nearby Carlisle, Herbert, and Tana, comprises the Islands of Four Mountains group in the Aleutian arc. While it has been primarily classified as an "open-vent" system (per specification of Rose et al., 2013) due to persistent degassing from the summit crater, it has also exhibited repeated cycles of dome formation and destruction (de Angelis et al., 2021). Between 2005 and 2020, Cleveland saw frequent explosive eruptions, likely as a result of dome formation leading to a seal forming at the vent that in turn led to pressurisation of the system prior to an explosive event. Yet, due in large part to its remoteness and the associated difficulty of establishing a permanent network of instruments, few precursory signals have been recorded. In fact, prior to 2014, Cleveland volcano had no instruments despite having erupted every year since 2005. A significant amount of current knowledge on Cleveland's volcanic system has been derived from remote sensing techniques, such as gas flux (primarily SO2) estimates from space and the detection of explosions using distant infrasound sites (de Angelis et al., 2012).