Seismic Activity and Magmatic Intrusions may Forecast Monogenetic Eruptions

11 Mar 2016

In a paper published in Geology, a peer-reviewed scientific journal published by Geological Society of America, Associate Professor Fidel Costa from the Earth Observatory of Singapore and colleagues Helena Albert and Joan Martí from the Central Geophysical Observatory in Spain found that monogenetic eruptions could be anticipated by a combination of seismic and petrological observations. 

Seismic activity, ground deformation, and gas activity are usually recorded before volcanic eruptions, especially those with a rich eruptive history. However, there is a category of volcanoes called monogenetic, that erupt just once and at unexpected locations. Thus it is challenging to monitor them or anticipate their eruptions with the same accuracy. The difficulty is further compounded by a lack of instrumental monitoring data, since few of these eruptions have occurred in the recent past.

Given the challenges of anticipating the formation of a future monogenetic volcano, Costa et al compiled all the previously available petrological information and combined with new historical accounts for seismicity and proposed a new conceptual model to link the two. Some monogenetic fields are located in areas with high population densities or which are popular tourist destinations. An eruption, even if small in size, in these areas could lead to economic loss and casualties.

The researchers focused on monogenetic volcanoes located mainly on the Canary Islands, Iceland, Papua New Guinea, Mexico, and Japan, using a combination of available monitoring data for unrest and historical account of felt seismicity. They found a pattern in the seismic activity in these areas: it begins one or two years prior to an eruption, intensifying at two to three months, and later, one week to a fortnight before erupting.

An analysis of the lava’s petrological and geochemical characteristics indicated also that multiple batches of magma intruded in a subvolcanic reservoir. The time frames of the multiple magma intrusions coincide with seismic activity and reflect that the pressure from rising magma fractures the rocks in its path to the surface. These fractures filled with magma are called dikes; many dikes do not reach the Earth’s surface but still would give seismicity. However, the location of these dikes and associated seismicity could indicate the possible locations of future monogenetic volcanoes.

Studying the seismicity and petrological characteristics of intrusive magma from monogenetic fields offers an insight into the locations of future eruptions, improving forecasting and, subsequently, mitigating the risks associated with these volcanoes.

The paper is open access and available for download here.

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