SINOOK _________________________________________________________________________________________________________ NSF Workshop: Drilling active tectonics and magmatism Park City, UT • May 28-30, 2013 1 Sampling and In-situ Observations of Okmok (SINOOK) Timothy Masterlark 1 , John Eichelberger 2 , Jeffrey Freymueller 2 , Matthew Haney 3 , Shaul Hurwitz 4 , Pavel Izbekov 2 , Jessica Larsen 2 , Setsuya Nakada 5 , Christina Neal 3 , William Roggenthen 1 , and Clifford Thurber 6 . 1 South Dakota School of Mines and Technology, Rapid City, SD 57701, USA. 2 University of Alaska Fairbanks, Fairbanks, AK 99775, USA. 3 Alaska Volcano Observatory, U.S. Geological Survey, Anchorage, AK 99508, USA. 4 U.S. Geological Survey, Menlo Park, CA 94025, USA. 5 ERI, University of Tokyo, Japan. 6 University of Wisconsin-Madison, Madison, WI 53706, USA. Project Summary SINOOK will drill the caldera of Okmok volcano, Alaska (Figure 1), and collect core and fluid samples, temperature measurements, and borehole stress measurements to a depth of 4 kilometers. Ideally, the sampling will penetrate the transition zone between the country rock and the magma chamber and culminate with direct sampling of quenched magma. This assemblage of in situ information will provide unprecedented constraints for interdisciplinary models of deformation, stress, geothermal systems, eruption history, and caldera formation for this active volcano. SINOOK will address an array of important scientific questions for the specific example of Okmok volcano and have far-reaching interdisciplinary implications. Scientific Questions addressed by SINOOK: 1. How reliable are estimates and uncertainties for internal processes and structures of volcanoes, determined from geophysical surface observations? SINOOK will verify geophysical models determined from seismic tomography, reflection, and anisotropy; gravity; and geodesy. For example, are the in situ or laboratory based rock properties (collected by SINOOK) within uncertainties of surface-based geophysical models? Results will have important implications for the reliability of geophysical models for Okmok volcano and elsewhere, as well as influence the justification and scope of major geophysical data collection initiatives for other volcanoes. 2. What is the magma migration and storage and eruption style in space and time? What are the systematic and asystematic aspects of eruption cycles? Results and implications may be transferrable to the general understanding of other volcanoes in island arc settings. 3. What is the basic structure of the magma chamber? Is it a single finite chamber, an assembly of dike and sill structures, or a multiphasic mush zone? The answer to this question has important implications for magma migration and storage, as well as understanding the conditions that lead to specific eruption styles. 4. What is the rheologic structure of the transition zone separating the magma chamber from the country rock? Results that combine in situ observations and laboratory experiments will have implications for understanding the magma replenishment, as determined from geodetic data. 5. What are the characteristics and interactions of the shallow groundwater and deeper hydrothermal systems? How do these fluid systems influence the eruption style? The 2008 hydrovolcanic eruption was very different from the effusive 1997 eruption, even though both eruptions tapped the same magma source. The answers to these questions have important implications for understanding the evolution of eruption styles for other volcanoes, as well as for unraveling the complexity volcanic geothermal systems. 6. How does dike propagation couple to the local stress field and loading in the complex domain of a caldera? Results have strong implications for geothermal and hydrocarbon production, as well as nuclear waste disposal strategies, and are thus aligned with Energy and Economic interests. 7. How do eruption cycles integrate with ecological and local societal systems? Eruption cycles present examples of stress and recovery episodes with relevance to interdisciplinary ecological, societal, and economic systems. 8. What are the long-range ash plume or climate impacts? Determining the frequency, scale, and style of eruptions will have important implications for major civilian and military air traffic corridors that intersect Aleutian airspace. Although scientific drilling of Okmok’s caldera is the kernel of SINOOK, the project will include both pre- and post- drilling components that span field, laboratory, remote sensing, and computational activities. While these activities are dominated by geologic and geophysical studies, the scientific questions above demonstrate great potential for interdisciplinary studies that naturally integrate Earth science with ecology, cultural studies, economics, and energy interests. Pre-drilling geophysical surveys (e.g., gravity, MT, EM, and seismic) will sharpen our understanding of the caldera’s interior and provide guidance for drilling operations. Furthermore, these high resolution 3D models, developed using state- of-the-art geophysical instruments and methods, will be confronted with in situ observations in verification analyses. Auxiliary boreholes will be drilled to collect complementary information before, during, and after the main drilling operation. Downhole geophysical instruments will be deployed in the main borehole to collect geophysical information that will leverage co-drilling measurements and provide a basis for future complementary studies of this dynamic volcano.