Why study volcanoes?
At first glance, a textbook might give the impression that we have volcanoes all figured out. In reality, scientists are still grappling with what might seem like fundamental questions. One of the overarching questions I aim to address is:
How can we better forecast the onset, intensity, and duration of eruptions?
To answer this critical question, we must deepen our understanding of magma storage and ascent processes. My research utilizes high-pressure, high-temperature experimental methods to investigate the key processes occurring within volcanoes, from magma storage regions to the volcanic conduit.
How much melt is in the magma storage region?
…and how much is eruptible?
These are critical questions for volcanic hazard assessment. Seismology plays a key role in understanding the Earth's interior, forecasting volcanic eruptions, and characterizing magma reservoirs. Recent seismic experiments, supported by the GeoPRISMS and EarthScope Programs of the U.S. National Science Foundation, have yielded higher-resolution tomographic models of magma reservoirs, revealing previously unknown structures beneath volcanoes.
Despite advancements in 3D seismic data acquisition and processing, quantitatively interpreting these data remains challenging. A major complication arises when attempting to translate modeled seismic velocity delays into actual melt percentages. This uncertainty can impact the accuracy of volcanic hazard assessments. To better constrain these estimates, it's essential to consider both compositional effects and the geometric distribution of melt within a porous matrix.
What causes transitions in eruption style?
Transitions in the eruptive style of mafic magmas remain poorly understood. While silicic systems are more frequently researched and publicized due to their explosive nature, mafic volcanoes represent the most common form of volcanism on Earth. These volcanoes exhibit a wide range of eruption styles, typically characterized by effusive activity. However, changes in flow dynamics can lead to explosive, ash-generating episodes. The efficiency of volatile degassing from ascending magma plays a critical role in determining the eruptive style. Magma can degas through several mechanisms during ascent, including permeable wall rocks, viscous shear along conduit walls, or the formation of a permeable foam. Experimental methods allow us to constrain the threshold conditions that facilitate permeability development, providing insights into these complex processes.
What do pyroclasts tell us?
Pyroclasts, the fragments of magma ejected during an eruption, hold valuable clues about the conditions within a volcano. By quantitatively analyzing their chemical compositions and textures, we can infer details about magma storage conditions and the processes occurring within the conduit. Experiments are essential in constraining the pressure, temperature, volatile content, and timescales under which these textures form. The results from these experiments are then integrated into rheological models, which help explain the size, duration, and style of volcanic eruptions.