Growth and collapse of the 2018–2019 lava dome of Merapi volcano

Abstract

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Hidden mechanical weaknesses within lava domes provided by buried high-porosity hydrothermal alteration zones

“…This finding is qualitative, however, especially since optical effects by hydro-meteorological conditions are commonly challenging for photogrammetric methods, but our drone analysis provides nevertheless a first-order estimate on the increase of sulfuric deposition and acid sulfate alteration. The area of the southern sector was covered by renewed dome lava extrusion in 2018, but subsequently collapsed and is now the site of frequent mass wasting events and the origin of pyroclastic density currents during the recent (post 2019) crisis of Merapi volcano 10 , 26 , 42 (see also below).

Figure 3 Temporal changes at Merapi summit dome.

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“…3 ) and then partially collapsed producing a hazardous pyroclastic density current in 2019 (Refs. 10 , 26 , 42 ). Moreover, this area is also the site of frequent mass wasting events, and thus the origin of pyroclastic density currents, during the most recent (post 2019) crisis at Merapi volcano.…”

“…Catastrophic volcano dome collapse is a highly hazardous, but poorly understood, phenomenon. Historic and recent global examples of dome or partial dome collapse include Soufrière Hills volcano, Montserrat in 1998–1999 1 , Unzen volcano, Japan in 1991 2 , Mount Hood and Mount Rainier in USA 3 , 4 , La Soufrière de Guadeloupe in the Eastern Caribbean 5 , Santiaguito in Guatemala 6 , Volcán de Colima in Mexico 7 , and Merapi and Sinabung volcanoes in Indonesia in 2010 and 2013–2014, respectively 8 – 10 . Crucially, it has been observed that the debris avalanche materials resulting from such dome collapse events frequently contain moderately to highly altered rock clasts, pointing towards a likely crucial role for pre-collapse mechanical weakening of these dome complexes as a result of hydrothermal alteration 11 , 12 .…”

Constructive and Destructive Processes During the 2018–2019 Eruption Episode at Shiveluch Volcano, Kamchatka, Studied From Satellite and Aerial Data

“…The details of such growth and collapse, however, may be strongly dependent on the local site conditions. At Merapi, it was recently identified that the mechanism of collapse is controlled by the basement and dome slopes, which also control the directions of destruction episodes (Kelfoun et al, 2021). At Shiveluch, when considering the outlines and directions of the western (originating in 2005) and eastern (originating in 2010) collapse scars, we find that these azimuthal directions have a certain longevity.…”

“…The complex interrelation and even bidirectional interaction of events responsible for constructing and destroying the volcano edifice have been identified for volcanoes worldwide, both on land (Germa et al, 2015) and in the ocean (Sibrant et al, 2014). The relevant observations range from local-scale lava dome growth and collapse (Kelfoun et al, 2021) to large-scale ocean islands, where collapse-related unloading even affects deep crustal magma reservoirs (Manconi et al, 2009). The details of such growth and collapse, however, may be strongly dependent on the local site conditions.…”