International audienceA 1.6 km riser borehole was drilled at site C0009 of the NanTroSEIZE, in the center of the Kumano forearc basin, as a landward extension of previous drilling in the southwest Japan Nankai subduction zone. We determined principal horizontal stress orientations from analyses of borehole breakouts and drilling-induced tensile fractures by using wireline logging formation microresistivity images and caliper data. The maximum horizontal stress orientation at C0009 is approximately parallel to the convergence vector between the Philippine Sea plate and Japan, showing a slight difference with the stress orientation which is perpendicular to the plate boundary at previous NanTroSEIZE sites C0001, C0004 and C0006 but orthogonal to the stress orientation at site C0002, which is also in the Kumano forearc basin. These data show that horizontal stress orientations are not uniform in the forearc basin within the surveyed depth range and suggest that oblique plate motion is being partitioned into strike-slip and thrusting. In addition, the stress orientations at site C0009 rotate clockwise from basin sediments into the underlying accretionary prism

Abstract. We describe the creation of a data set describing changes related to the presence of ice sheets, including ice-sheet extent and height, ice-shelf extent, and the distribution and elevation of ice-free land at the Last Glacial Maximum (LGM), which were used in LGM experiments conducted as part of the fifth phase of the Coupled Modelling Intercomparison Project (CMIP5) and the third phase of the Palaeoclimate Modelling Intercomparison Project (PMIP3). The CMIP5/PMIP3 data sets were created from reconstructions made by three different groups, which were all obtained using a model-inversion approach but differ in the assumptions used in the modelling and in the type of data used as constraints. The ice-sheet extent in the Northern Hemisphere (NH) does not vary substantially between the three individual data sources. The difference in the topography of the NH ice sheets is also moderate, and smaller than the differences between these reconstructions (and the resultant composite reconstruction) and ice-sheet reconstructions used in previous generations of PMIP. Only two of the individual reconstructions provide information for Antarctica. The discrepancy between these two reconstructions is larger than the difference for the NH ice sheets, although still less than the difference between the composite reconstruction and previous PMIP ice-sheet reconstructions. Although largely confined to the ice-covered regions, differences between the climate response to the individual LGM reconstructions extend over the North Atlantic Ocean and Northern Hemisphere continents, partly through atmospheric stationary waves. Differences between the climate response to the CMIP5/PMIP3 composite and any individual ice-sheet reconstruction are smaller than those between the CMIP5/PMIP3 composite and the ice sheet used in the last phase of PMIP (PMIP2).

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Abstract. We describe the creation of boundary conditions related to the presence of ice sheets, including ice sheet extent and height, ice shelf extent, and the distribution and altitude of ice-free land, at the Last Glacial Maximum (LGM) for use in LGM experiments conducted as part of the fifth phase of the Coupled Modelling Intercomparison Project (CMIP5) and the third phase of the Palaeoclimate Modelling Intercomparison Project (PMIP3). The CMIP5/PMIP3 data sets were created from reconstructions made by three different groups, which were all obtained using a model-inversion approach but differ in the assumptions used in the modelling and in the type of data used as constraints. The ice sheet extent, and thus the albedo mask, for the Northern Hemisphere (NH) does not vary substantially between the three individual data sources. The difference in the topography of the NH ice sheets is also moderate, and smaller than the differences between these reconstructions (and the resultant composite reconstruction) and ice-sheet reconstructions used in previous generations of PMIP. Only two of the individual reconstructions provide information for Antarctica. The discrepancy between these two reconstructions is larger than the difference for the NH ice sheets although still less than the difference between the composite reconstruction and previous PMIP ice-sheet reconstructions. Differences in the climate response to the individual LGM reconstructions, and between these reconstructions and the CMIP5/PMIP3 composite, are largely confined to the ice-covered regions, but also extend over North Atlantic Ocean and Northern Hemisphere continents through atmospheric stationary waves. There are much larger differences in the climate response to the latest reconstructions (or the derived composite) and ice-sheet reconstructions used in previous phases of PMIP.

The Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) program is a coordinated, multiexpedition drilling project designed to investigate fault mechanics and seismogenesis along subduction megathrusts through direct sampling, in situ measurements, and long-term monitoring in conjunction with allied laboratory and numerical modeling studies. The fundamental scientific objectives of the NanTroSEIZE drilling project include characterizing the nature of fault slip and strain accumulation, fault and wall rock composition, fault architecture, and state variables throughout the active plate boundary system. The primary goals for Integrated Ocean Drilling Program (IODP) Expedition 319 are riser drilling, analyses of cuttings and limited cores, logging, and casing at proposed Site NT2-11B (or alternate proposed Site NT2-11A) and riserless drilling, logging while drilling (LWD), and casing at proposed Site NT2-01J (or alternate proposed Site NT2-01K). Operations at both sites will include placing a wellhead and drilling and casing to the target depth in preparation for installation of monitoring equipment planned for future expeditions. This Scientific Prospectus outlines the scientific rationale, objectives, and operational plans for drilling these two sites.Proposed Site NT2-11B is a riser drilling site located in the Kumano forearc basin in the upper plate above the seismogenic and presumed locked portion of the plate boundary thrust system. During this expedition, proposed Site NT2-11B will be drilled to 1600 meters below seafloor (mbsf) to (1) determine the composition, physical properties, and stratigraphy of the basin sediments, (2) conduct downhole measurements to determine stress magnitude and orientation and pore pressure magnitudes, (3) install casing in preparation for a riser observatory, and (4) acquire data from a two-ship vertical seismic profile experiment to characterize the rock volume surrounding and below the borehole, including the subduction thrust at a depth of ~10 km. The observatory (planned for installation in 2010 or 2011) will monitor seismicity, volumetric strain, tilt, pore pressure, and temperature, with the goals of characterizing strain accumulation and release, microseismicity, hydrologic transients associated with strain events, and ambient pore pressure and temperature. Proposed Site NT2-01J is a riserless drilling site located 3.5 km along strike of previously drilled and cored IODP Site C0004 and will penetrate a major splay fault ("megasplay") at ~410 mbsf. The objectives at this site are to (1) collect measurement while drilling (MWD) and LWD data that will complement LWD and core data collected during IODP Expeditions 314 and 316 at Site C0004, (2) install casing in preparation for installation of an observatory (planned for 2010 or 2011) that will cross the fault Expedition 319 Scientific Prospectus 4 zone and extend into the footwall, and (3) install a temporary instrument package that will monitor pore pressure and temperature within a screened interval spanning th...