This chapter contains sections titled: Introduction Frictional Strength of Faults Anticipated Melt Thickness from Adiabatic Melting Characteristics of Fault-Generated Pseudotachylyte Scarcity of Pseudotachylyte Energy Comparisons Factors Inhibiting Melting Discussion
Research Article| September 27, 2017 Real‐Time Earthquake Monitoring during the Second Phase of the Deep Fault Drilling Project, Alpine Fault, New Zealand Calum J. Chamberlain; Calum J. Chamberlain aSchool of Geography, Environment and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand, calum.chamberlain@vuw.ac.nz Search for other works by this author on: GSW Google Scholar Carolin M. Boese; Carolin M. Boese bInstitute of Earth Science and Engineering, University of Auckland, Auckland 1010, New ZealandiNow at Goethe University Frankfurt, Institute of Geosciences, Altenhöferallee 1, 60438 Frankfurt, Germany. Search for other works by this author on: GSW Google Scholar Jennifer D. Eccles; Jennifer D. Eccles cScience Centre, University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand Search for other works by this author on: GSW Google Scholar Martha K. Savage; Martha K. Savage aSchool of Geography, Environment and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand, calum.chamberlain@vuw.ac.nz Search for other works by this author on: GSW Google Scholar Laura‐May Baratin; Laura‐May Baratin aSchool of Geography, Environment and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand, calum.chamberlain@vuw.ac.nz Search for other works by this author on: GSW Google Scholar John Townend; John Townend aSchool of Geography, Environment and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand, calum.chamberlain@vuw.ac.nz Search for other works by this author on: GSW Google Scholar Anton K. Gulley; Anton K. Gulley cScience Centre, University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand Search for other works by this author on: GSW Google Scholar Katrina M. Jacobs; Katrina M. Jacobs dGNS Science, P.O. Box 30‐368, Lower Hutt 5040, New Zealand Search for other works by this author on: GSW Google Scholar Adrian Benson; Adrian Benson aSchool of Geography, Environment and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand, calum.chamberlain@vuw.ac.nz Search for other works by this author on: GSW Google Scholar Sam Taylor‐Offord; Sam Taylor‐Offord dGNS Science, P.O. Box 30‐368, Lower Hutt 5040, New Zealand Search for other works by this author on: GSW Google Scholar Clifford Thurber; Clifford Thurber eDepartment of Geoscience, University of Wisconsin–Madison, 1215W Dayton Street, Madison, Wisconsin 53706 U.S.A. Search for other works by this author on: GSW Google Scholar Bin Guo; Bin Guo eDepartment of Geoscience, University of Wisconsin–Madison, 1215W Dayton Street, Madison, Wisconsin 53706 U.S.A. Search for other works by this author on: GSW Google Scholar Tomomi Okada; Tomomi Okada fResearch Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, Sendai 980‐8578, Japan Search for other works by this author on: GSW Google Scholar Ryota Takagi; Ryota Takagi fResearch Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, Sendai 980‐8578, Japan Search for other works by this author on: GSW Google Scholar Keisuke Yoshida; Keisuke Yoshida gNational Research Institute for Earth Science and Disaster Prevention, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan Search for other works by this author on: GSW Google Scholar Rupert Sutherland; Rupert Sutherland aSchool of Geography, Environment and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand, calum.chamberlain@vuw.ac.nz Search for other works by this author on: GSW Google Scholar Virginia G. Toy Virginia G. Toy hDepartment of Geology, University of Otago, Dunedin 9054, New Zealand Search for other works by this author on: GSW Google Scholar Seismological Research Letters (2017) 88 (6): 1443–1454. https://doi.org/10.1785/0220170095 Article history first online: 27 Sep 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Calum J. Chamberlain, Carolin M. Boese, Jennifer D. Eccles, Martha K. Savage, Laura‐May Baratin, John Townend, Anton K. Gulley, Katrina M. Jacobs, Adrian Benson, Sam Taylor‐Offord, Clifford Thurber, Bin Guo, Tomomi Okada, Ryota Takagi, Keisuke Yoshida, Rupert Sutherland, Virginia G. Toy; Real‐Time Earthquake Monitoring during the Second Phase of the Deep Fault Drilling Project, Alpine Fault, New Zealand. Seismological Research Letters 2017;; 88 (6): 1443–1454. doi: https://doi.org/10.1785/0220170095 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search ABSTRACT The Deep Fault Drilling Project (DFDP) is a multinational scientific drilling effort to study the evolution, structure, and seismogenesis of the Alpine fault, New Zealand, via in situ measurements of fault rock properties. The second phase of drilling (DFDP‐2), undertaken in the Whataroa Valley in late 2014, was intended to intersect the Alpine fault at a depth of around 1 km. In conjunction with the drilling and on‐site science activities, a real‐time seismic monitoring scheme and traffic‐light response protocol were established to detect, locate, and if necessary respond to seismicity within 30 km of the drill site. This network was operated around the clock between late August 2014 and early January 2015, and we detected and located 493 earthquakes of ML 0.6–4.2. None of these earthquakes occurred within 3 km of the drill site, and nor did any of the seismicity detected require changes to drilling operations. The monitoring was undertaken using open‐source software operated by an international team of 16 seismologists (including eight postgraduate students) working in 7 institutions and 3 countries to provide rapid on‐ and off‐site manual checking and relocating of events. The team's standard response time between detection and final location was less than 30 min under normal background seismicity conditions and up to 1 hr during swarm activity and for low‐priority, distant (≥30 km epicentrally from the drill site) earthquakes. This article documents the methodology, infrastructure, protocols, outcomes, and key lessons of this monitoring. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Abstract A layer of substantially noncrystalline material, composed of partially annealed nanopowder with local melt, was experimentally generated by comminution during ∼1.5 mm total slip at ∼2.5 × 10 −6 m s −1 , P conf ∼ 0.5 GPa, and 450°C or 600°C, on saw cut surfaces in novaculite. The partially annealed nanopowder comprises angular grains mostly 5–200 nm diameter in a variably dense packing arrangement. A sharp transition from wall rock to partially annealed nanopowder illustrates that the nanopowder effectively localizes shear, consistent with generation of nanoparticles during initial fragmentation, not by progressive grain size reduction. Dislocation densities in nanopowder grains or immediate wall rock are not significantly high, but there are planar plastic defects spaced at 5–200 nm parallel to the host quartz grain's basal plane. We propose these plastic defects developed into through‐going fractures to generate nanocrystals. The partially annealed nanopowder has a crystallographic preferred orientation (CPO) that we hypothesize developed due to surface energy interactions to maximize coincident site lattices (CSL) during annealing. This mechanism may also have generated CPOs recently described in micro/nanocrystalline calcite fault gouges.
<p>There is currently around a 30% probability New Zealand&#8217;s Alpine Fault will accommodate another M~8 earthquake in the next 50 years. The fault passes through Franz Josef Glacier town, a popular tourist destination attracting up to 6,000 visitors per day during peak season. The township straddles the fault, with building stock and infrastructure likely to be affected by at least 8m horizontal and 1.5m vertical ground displacements in this coming event. New Alpine Fault science is presented here that adds to the strong evidence in support of moving the township northward and out of a 200m zone of deformation across the fault zone to mitigate future losses.</p><p>In 2011 two shallow boreholes were drilled at Gaunt Creek, as part of the Alpine Fault Drilling Project, DFDP. In cores collected from the deeper of these boreholes (DFDP-1B), two &#8216;principal slip zones (PSZ)&#8217; were sampled, indicating the fault is not a simple geometrical structure. Subsequent studies of the recovered cores have demonstrated:</p><ol><li>The lower of the two PSZ in DFDP-1B has particle size distributions indicating it accommodated more coseismic strain than the shallower PSZ</li> <li>The PSZs sampled in the two boreholes have authigenic clay mineralogies diagnostic of different temperatures</li> </ol><p>These studies, combined with other recent outcrop studies nearby, highlight that the central Alpine Fault zone is a complex structure comprising multiple PSZ in the near surface, some of which may have been simultaneously active in past earthquakes. The results support previous studies (e.g. lidar mapping of offset Quaternary features) that underpinned definition of an &#8216;avoidance zone&#8217; around the fault trace in the town. Sadly, local government has failed to acknowledge this risk in public legislature in a way that adequately protects tourism and community infrastructure, and the >1.3 million visitors passing through the region each year. We will explain other actions consequently taken to build awareness and resilience to this hazard.</p>
Abstract The lattice preferred orientation (LPO) of both muscovite and biotite were measured by electron backscatter diffraction (EBSD) and these data, together with the LPOs of the other main constituent minerals, were used to produce models of the seismic velocity anisotropy of the Alpine Fault Zone. Numerical experiments examine the effects of varying modal percentages of mica within the fault rocks. These models suggest that when the mica modal proportions approach 20% in quartzofeldspathic mylonites the intrinsic seismic anisotropy of the studied fault zone is dominated by mica, with the direction of the fastest P and S wave velocities strongly dependent on the mica LPOs. The LPOs show that micas produce three distinct patterns within mylonitic fault zones: C-fabric, S-fabric and a composite S–C fabric. The asymmetry of the LPOs can be used as kinematic indicators for the deformation within mylonites. Kinematic data from the micas matches the kinematic interpretation of quartz LPOs and field data. The modelling of velocities and velocity anisotropies from sample LPOs is consistent with geophysical data from the crust under the Southern Alps. The Alpine Fault mylonites and parallel Alpine schists have intrinsic P-wave velocity anisotropies of 12% and S-wave anisotropies of 10%.
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