Japan Geoscience Union Meeting 2015

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International Session (Oral)

Symbol S (Solid Earth Sciences) » S-SS Seismology

[S-SS02] Frontier studies on subduction zone megathrust earthquakes and tsunamis

Mon. May 25, 2015 4:15 PM - 6:00 PM IC (2F)

Convener:*Kyuichi Kanagawa(Graduate School of Science, Chiba University), Demian Saffer(Dept. of Geosciences, The Pennsylvania State University, USA), Michael Strasser(Geological Institute, Seiss Federal Insitute of Technology ETH Zurich), Yasuhiro Yamada(Depertment of Urban Management Engineering, Kyoto University), Shuichi Kodaira(Institute for Research on Earth Evolution Japan Agency for Marine-Earth Science and Technology), Ryota Hino(International Research Institute of Disaster Science, Tohoku University), Kohtaro Ujiie(Graduate School of Life and Environmental Sciences, University of Tsukuba), Yoshihiro Ito(Disaster Prevention Research Institute, Kyoto University), Chair:Kohtaro Ujiie(Graduate School of Life and Environmental Sciences, University of Tsukuba), Kyuichi Kanagawa(Graduate School of Science, Chiba University)

4:15 PM - 4:35 PM

★ [SSS02-20] Unlocking the secrets of slow slip at the Hikurangi subduction margin

*Laura WALLACE1, Demian SAFFER2, Yoshihiro ITO3, Stuart HENRYS4, Philip BARNES5, Kimihiro MOCHIZUKI6, Joshu MOUNTJOY5, Stephen BANNISTER4, Michael UNDERWOOD7, Shuichi KODAIRA8, Rob HARRIS9 (1.University of Texas, Institute for Geophysics, 2.Pennsylvania State University, 3.Kyoto University, 4.GNS Science, New Zealand, 5.NIWA, New Zealand, 6.University of Tokyo, ERI, 7.University of Missouri, 8.JAMSTEC, 9.Oregon State University)

Keywords:subduction, slow slip events, GPS, scientific drilling, seafloor geodesy, New Zealand

The northern Hikurangi subduction margin, New Zealand is the site of the shallowest well-documented slow slip events (SSEs) on Earth. Due to the close proximity of the SSE source area to the seafloor at the offshore Hikurangi margin (<5-15 km), it has become an important international target for a variety of geophysical studies to understand the offshore physical mechanisms that lead to slow slip. The centerpiece of these efforts is a series of IODP proposals to undertake riserless (Joides Resolution) and riser (Chikyu) drilling, and CORK observatory installation on a transect spanning the shallow Hikurangi SSEs. We understand that if scheduling of riserless drilling (and observatory installation) occurs, it is likely for 2017. We will discuss the plans and scientific objectives for both riser and riserless drilling, and borehole observatories. We will discuss other ongoing experiments at the northern Hikurangi margin, including an upcoming heatflow survey, and recent seafloor geodetic (Absolute Pressure Gauges) and OBS deployments to undertake near-source investigations of SSE deformation and related seismicity of the shallow (<10 km depth) subduction thrust (the HOBITSS project). We will also present preliminary analysis of slip distribution and seismicity (using onshore data) from a large SSE that occurred in October 2014 directly beneath the HOBITSS network.