Abstract
Dome-building volcanoes often develop by intrusion and extrusion, recurrent destabilization and sector collapses, and renewed volcanic growth inside the collapse embayment. However, details of the structural architecture affiliated with renewed volcanic activity and the influences of regional structures remain poorly understood. Here, we analyze the recent activity of Shiveluch volcano, Kamchatka Peninsula, characterized by repeated episodes of lava dome growth and destruction due to large explosions and gravity-driven collapses. We collect and process a multisensor dataset comprising high-resolution optical (aerial and tri-stereo Pleiades satellite), radar (TerraSAR-X and TanDEM-X satellites), and thermal (aerial and MODIS, Sentinel-2, and Landsat 8 satellites) data. We investigate the evolution of the 2018–2019 eruption episode and evaluate the morphological and structural changes that led to the August 29, 2019 explosive eruption and partial dome collapse. Our results show that a new massive lava lobe gradually extruded onto the SW flank of the dome, concurrent with magmatic intrusion into the eastern dome sector, adding 0.15 km3 to the lava dome complex. As the amphitheater infilled, new eruption craters emerged along a SW-NE alignment close to the amphitheater rim. Then, the large August 29, 2019 explosive eruption occurred, followed by partial dome collapse, which was initially directed away from this SW-NE trend. The eruption and collapse removed 0.11 km3 of the dome edifice and led to the formation of a new central SW-NE-elongated crater with dimensions of 430 m × 490 m, a collapse scar at the eastern part of the dome, and pyroclastic density currents that traveled ∼12 km downslope. This work sheds light on the structural architecture dominated by a SW-NE lineament and the complex interplay of volcano constructive and destructive processes. We develop a conceptual model emphasizing the relevance of structural trends, namely, 1) a SW-NE-oriented (possibly regional) structure and 2) the infilled amphitheater and its decollement surface, both of which are vital for understanding the directions of growth and collapse and for assessing the potential hazards at both Shiveluch and dome-building volcanoes elsewhere.
Highlights
Volcanic edifices develop as a result of interactions between volcano growth and mass wasting - constructive and destructive processes, respectively
A massive lava lobe developed at the dome during the extrusive period of December 2018 – April 2019, while a 430 m × 490 m SW–NE-elongated crater formed during the explosive eruption on August 29, 2019, which led to the significant destruction of the NE sector and the collapse of the eastern flank of the dome
The likely cause for the explosion and partial dome collapse is a blockage of the vent caused by the massive 2018 lava lobe extrusion, inducing endogenous swelling on the eastern dome flank
Summary
Volcanic edifices develop as a result of interactions between volcano growth and mass wasting - constructive and destructive processes, respectively. The catastrophic sector collapses that occurred at Bezymianny in 1956 (Gorshkov, 1959; Belousov and Belousova, 1998), at Mount St. Helens in 1980 (Lipman and Mullineaux, 1981) and at Anak Krakatau, Indonesia, in 2018 (Walter et al, 2019) resulted in the formation of large and wide-open collapse amphitheaters that span 0.5–2 km in width; in contrast, smallerscale partial dome collapses, e.g., those that occurred at Soufriere Hills, Montserrat, in 1997 (Voight et al, 2002) and 2010 (Stinton et al, 2014) and at Merapi, Indonesia, in 2006 (Ratdomopurbo et al, 2013), produce narrower collapse scars and are more common
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