Located at the junction of Kamchatka and the Aleutian Arc, the Klyuchevskoy Volcanic Group is arguably the most active island arc volcanic center in the world. Frequent and violent eruptions of its member volcanoes present both an immediate hazard to trans-Pacific air traffic and may have long-term climate implications. Ash from erupting Klyuchevskoy Group volcanoes has been tracked for thousands of miles away from Kamchatka and presents a serious threat to jet engines at high altitudes. Input of large volumes of volcanic ash into the atmosphere has been shown to impact global climate, causing multiple years of depressed temperatures following large eruptions. Yet, despite representing one of the largest volcanic features on the planet, the geodynamic mechanism to drive activity of the Klyuchevskoy Group is poorly understood. When the activity, size and position of the Klyuchevskoy Group is considered in the framework of regional tectonics it becomes apparent that this volcanic cluster simply can not exist in its present form. The position of the Klyuchevskoy relative to the subducting Pacific greatly exceeds typical depths of melt generation for arc volcanoes, and it is not clear where the lavas erupting at the Klyuchevskoy Groups are generated. This projects aims to put new seismological and geochemical constraints on the upper mantle structure beneath the Klyuchevskoy Group and shed light on the mechanism driving volcanic activity at this volcanic center. It is motivated by our previous research effort which identified anomalous feature in the upper mantle beneath the Klyuchevskoy Group which we believe holds the key to understanding the mechanism driving activity of this volcanic center.
We propose a detailed investigation of the anomaly we have identified within the mantle wedge beneath the Klyuchevskoy Group, coupled with an effort to relate geochemical tracers present in Klyuchevskoy Group lavas to the proposed seismic feature. The seismic study will utilize new data acquired in the framework of the ongoing NSF Partnership in Researh and Education (PIRE) effort in Kamchatka. We will use different types of teleseismic receiver function analysis to investigate the mantle wedge beneath the Klyuchevskoy Group. In parallel we will assemble a comprehensive database of geochemical information on KG lavas, using databases, published literature and emerging results from ongoing work. The ultimate goal of the project is to develop a geodynamic scenario for the Klyuchevskoy Group, informed by the seismic structure of the mantle wedge beneath it, and the geochemistry of lavas it produces.
This project is supported by the Geophysics and Petrology & Geochemistry Programs.
This project was a joint effort between Rutgers and The College of New Jersey to examine the Klyuchevskoy Volcanic Group, which is composed of one of the most productive island arc volcanoes in the world. The project focused a coupled seismic and petrologic investigation beneath the Klyuchevskloy Group, where a small pilot study identified a small dipping planar feature about 110 km in depth. Through this project, the Rutgers group developed a common conversion point stacking technique to be used with extended-time multi-taper computed receiver functions. Then undergraduate students at The College of New Jersey worked with a graduate student from Rutgers to apply the technique to data from seismic stations located in the Kamchatka peninsula. Resulting images showed a sharply bounded dipping feature at 110 km depth, that is distinct from the subducting Pacific plate located at 170 km depth in that region. Petrologic results from the lavas suggested that the melt source was pyroxenite, in addition to previously found peridotite source melts, suggesting that there are two different sources of melts in the mantle wedge feeding the volcanoes in this region. This project trained three undergraduate students, and allowed them all to spend significant time interacting with and gaining mentorship from a graduate student from a nearby university. They were able to ask him questions about graduate school life and career goals. The project also allowed for the graduate student to have some training in how to mentor undergraduates, in communicating with them effectively about project management, setting expectations, goal setting, and managing expectations. The undergraduates gained skills in MATLAB and PYTHON, general signal processing and programming, and seismic data processing. Two of the students went on to graduate study in the sciences, and one went on to a Masters in Teaching in science. This project also got the students excited to apply the technique they were learning about to data in areas in other parts of the world, and they wanted to derive and test their own hypotheses using the infrastructure derived within the context of this project.
