ORCID Profile
0000-0003-3983-9308
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Publisher: American Geophysical Union (AGU)
Date: 05-2017
DOI: 10.1002/2016JB013498
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-2670
Abstract: & & In response to the growing geo-societal challenges of our densely populated planet, current research frequently requires convergence of multiple research disciplines, and optimized use of openly available data, research facilities and funds. Such optimization is the main aim of many research infrastructures developing both at the national and international level. In the Netherlands, the European Plate Observing System & #8211 Netherlands (EPOS-NL) was formed, as the Dutch research infrastructure for solid Earth sciences. EPOS-NL aims to further develop world-class facilities for research into georesources and hazards, and to provide international access to these facilities and derived data. It is a partnership between Utrecht University, Delft University of Technology and the Royal Netherlands Meteorological Institute (KNMI) and is funded by the Dutch Research Council. EPOS-NL facilities include: 1) The Earth Simulation Lab at Utrecht University, 2) The Groningen gas field seismological network and the ORFEUS Data Center at KNMI, 3) The deep geothermal doublet (DAPwell), to be installed on the Delft university c us, and 4) A distributed facility for multi-scale imaging and tomography (MINT), shared between the Utrecht and Delft universities. EPOS-NL provides financial, technical and scientific support for access to these facilities. To get facility access, researchers can apply to a bi-annual call, with 2021 calls planned in Q1 and Q3. EPOS-NL further works with researchers, data centers and industry to provide access to essential data and models (e.g. pertaining to the seismogenic Groningen gas field) within the framework of the European infrastructure EPOS, conforming to FAIR (Findable, Accessible, Interoperable and Reusable) data principles. In that way, EPOS-NL contributes directly to a globally developing trend to make research facilities and data openly accessible to the international community. This supports cost-effective and multi-disciplinary research into the geo-societal challenges faced by our densely populated planet. See www.EPOS-NL.nl for more information.& &
Publisher: American Geophysical Union (AGU)
Date: 02-2016
DOI: 10.1002/2015JB012593
Abstract: The Alpine Fault, New Zealand, is a major plate‐bounding fault that accommodates 65–75% of the total relative motion between the Australian and Pacific plates. Here we present data on the hydrothermal frictional properties of Alpine Fault rocks that surround the principal slip zones (PSZ) of the Alpine Fault and those comprising the PSZ itself. The s les were retrieved from relatively shallow depths during phase 1 of the Deep Fault Drilling Project (DFDP‐1) at Gaunt Creek. Simulated fault gouges were sheared at temperatures of 25, 150, 300, 450, and 600°C in order to determine the friction coefficient as well as the velocity dependence of friction. Friction remains more or less constant with changes in temperature, but a transition from velocity‐strengthening behavior to velocity‐weakening behavior occurs at a temperature of T = 150°C. The transition depends on the absolute value of sliding velocity as well as temperature, with the velocity‐weakening region restricted to higher velocity for higher temperatures. Friction was substantially lower for low‐velocity shearing ( V 0.3 µm/s) at 600°C, but no transition to normal stress independence was observed. In the framework of rate‐and‐state friction, earthquake nucleation is most likely at an intermediate temperature of T = 300°C. The velocity‐strengthening nature of the Alpine Fault rocks at higher temperatures may pose a barrier for rupture propagation to deeper levels, limiting the possible depth extent of large earthquakes. Our results highlight the importance of strain rate in controlling frictional behavior under conditions spanning the classical brittle‐plastic transition for quartzofeldspathic compositions.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2017
DOI: 10.1038/NATURE22355
Abstract: Temperature and fluid pressure conditions control rock deformation and mineralization on geological faults, and hence the distribution of earthquakes. Typical intraplate continental crust has hydrostatic fluid pressure and a near-surface thermal gradient of 31 ± 15 degrees Celsius per kilometre. At temperatures above 300-450 degrees Celsius, usually found at depths greater than 10-15 kilometres, the intra-crystalline plasticity of quartz and feldspar relieves stress by aseismic creep and earthquakes are infrequent. Hydrothermal conditions control the stability of mineral phases and hence frictional-mechanical processes associated with earthquake rupture cycles, but there are few temperature and fluid pressure data from active plate-bounding faults. Here we report results from a borehole drilled into the upper part of the Alpine Fault, which is late in its cycle of stress accumulation and expected to rupture in a magnitude 8 earthquake in the coming decades. The borehole (depth 893 metres) revealed a pore fluid pressure gradient exceeding 9 ± 1 per cent above hydrostatic levels and an average geothermal gradient of 125 ± 55 degrees Celsius per kilometre within the hanging wall of the fault. These extreme hydrothermal conditions result from rapid fault movement, which transports rock and heat from depth, and topographically driven fluid movement that concentrates heat into valleys. Shear heating may occur within the fault but is not required to explain our observations. Our data and models show that highly anomalous fluid pressure and temperature gradients in the upper part of the seismogenic zone can be created by positive feedbacks between processes of fault slip, rock fracturing and alteration, and landscape development at plate-bounding faults.
Publisher: Informa UK Limited
Date: 02-10-2017
Publisher: American Geophysical Union (AGU)
Date: 12-2017
DOI: 10.1002/2017GC007202
No related grants have been discovered for Andre Niemeijer.