Table 1 Objectives and methods for different evolutional stages of large-scale explosive eruptions
From: Volcanological challenges to understanding explosive large-scale eruptions
Stage | Possible timescale before climactic eruption | Magma process | Research targets | Possible observation techniques |
|---|---|---|---|---|
Stable | Up to 104–105 years | * Generation of silicic magmas by fractionation and/or crustal melting. * Accumulation of silicic magma within a shallow level of the earth’s crust | * Presence of magma chamber * Magma eruptability within the magma chamber *Prior eruptions from this volcano | * Seismic tomography * Electrical resistivity survey * Geological and petrological investigation of previous eruptions of this volcano |
Unrest | Less than 1 year (probably months)—years | * Destabilization of silicic magma chamber * Diking of the host rock and magma intrusion toward the surface | * Pressure condition inside the magma chamber * Dike intrusion process * Degassing during magma ascent | * Geodetic monitoring (ground and remote) * Seismicity monitoring * Gas geochemistry |
Onset of eruption | Less than 1 week—up to years | * Leaking of magma from the chamber * Decompression of magma chamber for collapse | * Pressure condition inside the magma chamber * Magma discharge rate and accumulative volume of erupting magma | * Geodetic monitoring (ground and remote) * Petrological investigation of erupted magmas * Seismicity monitoring * Gas geochemistry * Rader sensing (radar interferometry and single-shot views through clouds) |
Climactic eruption | N/A | * Extraction of magma from main body of the magma chamber * Collapse of the roof of magma chamber *Spreading of ignimbrite sheet | * Pressure condition inside the magma chamber * Magma discharge rate and accumulative volume of erupting magma * Behavior of ignimbrite | * Geodetic and seismic monitoring (if stations still alive) * Satellite remote sensing of ignimbrite spreading and of ash clouds and sulfate aerosol |