Collaborative Research: Deep structure controls on magmatic output of Klyuchevskoy volcanic group, Kamchatka.

Klyuchevskoy火山群位于堪察加和阿留申弧的交界处，可以说是世界上最活跃的岛弧火山中心。其成员火山频繁而猛烈的喷发既对跨太平洋空中交通构成直接威胁，也可能对气候产生长期影响。Klyuchevskoy Group火山喷发产生的火山灰在远离堪察加数千英里的地方被追踪到，并对高海拔的喷气式发动机构成严重威胁。大量火山灰进入大气已被证明会影响全球气候，导致在大规模喷发后多年的低气温。然而，尽管代表着地球上最大的火山地貌之一，但驱动Klyuchevskoy群活动的地球动力学机制却鲜为人知。当在区域构造框架内考虑Klyuchevskoy群的活动、规模和位置时，很明显，这个火山群根本不可能以目前的形式存在。Klyuchevskoy相对于俯冲太平洋的位置大大超过了弧形火山典型的熔体产生深度，目前尚不清楚Klyuchevskoy群喷发的熔岩是从哪里产生的。该项目旨在对Klyuchevskoy群下方的上地幔结构施加新的地震和地球化学约束，并阐明驱动该火山中心火山活动的机制。这是因为我们之前的研究工作发现了Klyuchevskoy群之下上地幔的异常特征，我们认为这是理解这个火山中心活动机制的关键。我们建议对Klyuchevskoy群下的地幔楔形体内发现的异常进行详细调查，并努力将Klyuchevskoy群熔岩中存在的地球化学示踪与拟议的地震特征联系起来。地震研究将利用在堪察加正在进行的国家科学基金会研究和教育伙伴关系(PERE)努力框架内获得的新数据。我们将使用不同类型的远震接收函数分析来研究Klyuchevskoy群下面的地幔楔体。同时，我们将利用数据库、已发表的文献和正在进行的工作的新成果，汇编一个关于KG熔岩的全面的地球化学信息数据库。该项目的最终目标是为Klyuchevskoy群开发一个地球动力学情景，了解其下方地幔楔体的地震结构及其产生的熔岩的地球化学。该项目得到地球物理和岩石学及地球化学计划的支持。

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.