caa a22 4500 606149198 CHVBK 20210128100533.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s00531-014-1115-5 doi (NATIONALLICENCE)springer-10.1007/s00531-014-1115-5 Shear behavior of DFDP-1 borehole samples from the Alpine Fault, New Zealand, under a wide range of experimental conditions [Elektronische Daten] [Matt Ikari, Sebastian Trütner, Brett Carpenter, Achim Kopf] The Alpine Fault is a major plate-boundary fault zone that poses a major seismic hazard in southern New Zealand. The initial stage of the Deep Fault Drilling Project has provided sample material from the major lithological constituents of the Alpine Fault from two pilot boreholes. We use laboratory shearing experiments to show that the friction coefficient µ of fault-related rocks and their precursors varies between 0.38 and 0.80 depending on the lithology, presence of pore fluid, effective normal stress, and temperature. Under conditions appropriate for several kilometers depth on the Alpine Fault (100MPa, 160°C, fluid-saturated), a gouge sample located very near to the principal slip zone exhibits µ=0.67, which is high compared with other major fault zones targeted by scientific drilling, and suggests the capacity for large shear stresses at depth. A consistent observation is that every major lithological unit tested exhibits positive and negative values of friction velocity dependence. Critical nucleation patch lengths estimated using representative values of the friction velocity-dependent parameter a−b and the critical slip distance D c , combined with previously documented elastic properties of the wall rock, may be as low as ~3m. This small value, consistent with a seismic moment M o =~4×1010 for an M w =~1 earthquake, suggests that events of this size or larger are expected to occur as ordinary earthquakes and that slow or transient slip events are unlikely in the approximate depth range of 3-7km. The Author(s), 2015 Fault nationallicence Friction nationallicence Earthquake nationallicence Alpine Fault nationallicence Scientific drilling nationallicence ICDP nationallicence DFDP nationallicence Ikari Matt MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany aut Trütner Sebastian MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany aut Carpenter Brett Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy aut Kopf Achim MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany aut International Journal of Earth Sciences Springer Berlin Heidelberg 104/6(2015-09-01), 1523-1535 1437-3254 104:6<1523 2015 104 531 https://doi.org/10.1007/s00531-014-1115-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00531-014-1115-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ikari Matt MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany aut NATIONALLICENCE 700 1- Trütner Sebastian MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany aut NATIONALLICENCE 700 1- Carpenter Brett Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy aut NATIONALLICENCE 700 1- Kopf Achim MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany aut NATIONALLICENCE 773 0- International Journal of Earth Sciences Springer Berlin Heidelberg 104/6(2015-09-01), 1523-1535 1437-3254 104:6<1523 2015 104 531