Magmatic Drivers of Eruption
What controls the location of volcanoes and the occurrence of eruptions?
Recent observations and innovations are fueling a new decadal effort in studying Magmatic Drivers of Eruption (MDE).
Magma pathways in the crust have been observed “lighting up”, with increases in seismic events between, prior to, between, and during eruptions and some magma storage regions “breathing” over the eruption eruptions. New petrological and geochemical studies have found that magma assembly, transport, and run-up to eruptions occur over timescales from hours to years, similar to timescales of observed volcanic unrest.
The SZ4D MDE implementation plan is motivated by scientific discoveries and societal urgency. Globally, almost 800 million people live in regions that are directly exposed to volcanic hazards , and the vast majority of these regions are in subduction zone settings.
The new focus of MDE is on the initiation of volcanic eruptions at subduction zones, as we recognize that there are new discoveries to be made that connect the most hazardous volcanoes on the planet today to underlying subduction drivers.
How do trans-crustal processes initiate eruptions at arc volcanoes?
A central question motivates MDE’s envisioned science activities: How do trans-crustal processes initiate eruptions at arc volcanoes? The trans-crustal magmatic system is instrumental in controlling eruption initiation and inter-eruptive unrest and quiescence. Processes within the trans-crustal system either prime or initiate volcanic eruptions outright or provide suitable conditions whereby intrusions and/or eruptions can be triggered by external drivers such as earthquakes or edifice collapse.
MDE’s central question and scientific framework can be articulated most clearly in terms of magmatic system controls and responses with the ultimate goals to identify underlying subduction drivers and develop useful eruption forecasts.
The MDE priorities evolve around three sets of hypotheses:
Eruption Precursors and Run-up Time
Gas and magma composition are linked to eruption precursors, run-up times, and eruption intensities
Plutonism, intrusion, and repose
Mantle magma production and supply rate are linked to the intrusive/extrusive mass budget, crustal residence time, repose time, and the evolution of crustal magmatic architecture
Eruption style, vigor, and duration
The periods and drivers of different external eruption triggers over timescales of minutes to >100,000 years are linked
Processes across multiple timescales and spanning the trans-crustal magmatic system impact subduction zone hazards near the surface. The goal of MDE research is to connect the volcanic system, the trans-crustal magmatic system, and the subduction system. These systems are typically treated separately, even though they are interrelated. For example, volcanic eruptions may be initiated rapidly by influx of mafic magmas from the mantle wedge. Different trans-crustal magmatic architectures may develop as a response to different mantle magma supply rates. More broadly, arc magmatic systems may respond to and drive FEC and L&S. For example, surface processes such as glacial unloading may lead to greater decompression melting in the mantle and greater eruptive frequency. SZ4D provides the opportunity to test different hypotheses for how subduction processes across a range of timescales - from minutes to millions of years - drive magmatism and volcanism, and the hazards associated with them. The column at right is an amalgamation of three separate cartoons (from the ERUPT report, NASEM, 2017), a reflection of the lack of current integration and the opportunity for SZ4D to make novel connections by drawing on evidence from active volcanoes, erupted deposits, and exhumed arc systems in four dimensions.
University of New Mexico
University of Rhode Island
University of Nevada Reno
Montana State University
US Geological Survey
University of Puerto Rico at Mayagüez
South Dakota School of Mines and Technology
California State University Fullerton
Oregon State University
Jacobs/NASA Johnson Space Center
Boise State University
Universidad de Chile
Pontificia Universidad Catholica de Chile
Laura Bono Troncoso
Álvaro Amigo Ramos