A sequence of a plinian eruption preceded by dome destruction at Kelud volcano, Indonesia, on February 13, 2014, revealed from tephra fallout and pyroclastic density current deposits

Abstract

A plinian-style eruption with a radially spreading umbrella cloud occurred on February 13, 2014, at Kelud volcano, Indonesia. We present the sequence of this plinian event based on a geological survey of the eruption products and analysis of satellite images. The eruptive deposits were divided into four major depositional units (Units A, B, C, and D) and used to determine the sequence of events. The plinian phase was preceded by partial destruction of the existing lava dome and generation of high-energy pyroclastic density currents (PDCs) mainly toward the NE that produced a series of depositional subunits (Units A0–2) and blown-down trees (stage 1). In the main phase of the plinian eruption, tephra fallout (Unit B) was widely distributed over East Java (stage 2). The winds above the volcano significantly affected the tephra dispersal process. In stage 3, the plinian column collapsed, generating dense PDCs that flowed down the volcano valleys, producing pumiceous lobate deposits (Unit C). The declining phase of the eruption produced fine-rich fallout tephra layers (Unit D1–2) from low-level eruption plumes and/or ash lofted from PDCs. The eruption sequence constructed from field observations is supported by geophysical observations. The deposit features and componentry suggest that newly ascended magma triggered the destruction of the lava dome and the generation of high-energy PDCs, and during the subsequent climactic phase the dome was completely destroyed. We estimate a total erupted volume of 0.25–0.50 km3 (bulk deposit volume, 0.14–0.28 km3 in dense rock equivalent) and a mass eruption rate of 6.5 ± 2.8 × 107 kg/s, with a volcanic explosivity index of 4. The eruption sequence and physical parameters of the 2014 eruption will help assess future volcanic activity and hazards at Kelud volcano.