Preexplosive conduit conditions during the 2010 eruption of Merapi volcano (Java, Indonesia)

Abstract

The 2010 eruption is the largest explosive event at Merapi volcano since 1872. The high energy of the initial 26 October explosions cannot be explained by simple gravitational collapse, and the paroxysmal explosions were preceded by the growth of a lava dome not large enough to ensure significant pressurization of the system. We sampled pumice from these explosive phases and determined the preexplosive depths of the pumices by combining textural analyses with glass water content measurements. Our results indicate that the magma expelled was tapped from depths of several kilometers. Such depths are much greater than those involved in the pre‐2010 effusive activity. We propose that the water‐rich magma liberated enough gas to sustain the explosivity. Our results imply that the explosive potential of volcanoes having dome‐forming, effusive activity is linked to the depth from which fresh magma can be evacuated in a single explosion, regardless of the evacuated volume.

Understanding Fast and Slow Unrest at Volcanoes and Implications for Eruption Forecasting

“…The juvenile material was both crystal-rich (Drignon et al, 2016) and volatile-rich, with melt inclusions reaching nearly 4 wt. % H 2 O and ∼3,000 ppm CO 2 (Preece et al, 2014) and matrix glasses up to 6.6 wt.…”

“…% H 2 O and ∼3,000 ppm CO 2 (Preece et al, 2014) and matrix glasses up to 6.6 wt. % H 2 O (Drignon et al, 2016) (Table 1). The pronounced inflationary behavior in October indicates that a batch of volatile-rich magma was quickly rising to shallow crustal levels below and into the volcano, followed by its appearance on the surface as a new lava dome grew during 1-4 November.…”

“…By contrast, "fast" behavior of 10 −2 -10 2 years is characteristic for erupting magmas, driven by the different reservoirs becoming interconnected at various spatial and temporal scales. Sources of data Castro and Dingwell, 2009Budi-Santoso et al, 2013Blundy et al, 2008Daag et al, 1996Major and Lara, 2013Drignon et al, 2016Carey and Sigurdsson, 1985Harlow et al, 1996Pallister et al, 2013Surono et al, 2012Cashman and Hoblitt, 2004Pallister et al, 1996Christiansen and Peterson, 1981Rutherford and Devine, 1996Endo et al, 1981Sabit et al, 1996Lipman et al, 1981Scott et al, 1996Moore and Albee, 1981White, 1996Rutherford et al, 1985Sarna-Wojcicki et al, 1981Wolfe and Hoblitt, 1996 erupting for 20 months in 2008-2009. Tephra fall and pyroclastic density current deposits dated at ∼9.4 ka may be associated with the summit caldera of the volcano (Naranjo and Stern, 2004).…”

Simulation of block‐and‐ash flows and ash‐cloud surges of the 2010 eruption of Merapi volcano with a two‐layer model

“…Pallister et al [] give a detailed description of the eruption chronology and estimate the extrusion rates. Budi‐Santoso et al [], Luehr et al [], and Jousset et al [] present the 2010 eruption from several geophysical points of view and Drignon et al [] based on textural analyses and glass water content. Cronin et al [], Charbonnier and Gertisser [], Komorowski et al [], and Jenkins et al [] provide a chronology of the eruption and map and describe the deposits.…”

“…The material included weathered and altered fragments, which were probably derived from the old summit dome complex [ Surono et al , ]. Drignon et al [] recently provided evidence that this initial stage of the eruption was magmatic: the conduit was plugged by the summit's old dome complex and filled with volatile‐rich magma. PDCs moved southward up to a distance of 7.5 km, following the Gendol valley that curves along the northwest side of the Kendil ridge (Figure ).…”