Can climate crisis evoke explosive eruptions?

Phreatic events are the most unpredictable forms of volcanic activity. These explosive eruptions result from hydrofracturing of the host rock when the pressure of subsurface fluids exceeds the failure threshold. Fluid pressures may be sufficiently increased by an adjacent magmatic heat source, by topographically driven hydrostatic head, or by fluid influx provided by large adjacent bodies of water, such as lakes and oceans. A combination of the latter two factors implies that the increase of mean sea level (MSL) in the Anthropocene may induce major perturbations of coastal volcanic hydrothermal systems. Here, we propose a case study to test the theory that increased MSL will affect fluid and heat flux of coastal volcanic hydrothermal systems. The case study will be conducted at three sites to improve the relevance of our findings. All are located in coastal regions with substantial tidal ranges, which will be used as a proxy to determine impacts of sea level variation on these systems. We selected the volcanic systems of Fagradalsfjall in Iceland, Ceboruco in Mexico, and Taranaki in New Zealand. For each site, we want to:

• Measure temperature profiles and derive zonal pressures in boreholes to map and investigate patterns of heat and fluid flux with relation to the tidal cycle.
• Interrogate magnetotelluric (MT) survey data for information about thermal structure, and distribution and chemistry of fluids and clay mineralogy
• Collect rocks samples to:
• Measure the complex conductivity of lithologies from the MT survey area to better interpret the correlation between MT data and physical rock properties
• Determine the fracture criteria of the host rocks related to pore pressure
• Create an integrated hydromechanical model for each volcanic system.

We hope to provide some insight on how the increasing MSL in the present day will impact hydrothermal systems leading to explosive eruptions.