A5050542006- earthquake and tectonic studies
- High-pressure geophysics and materials
- Seismology and Earthquake Studies
- Earthquake Detection and Analysis
- Seismic Imaging and Inversion Techniques
- Seismic Waves and Analysis
- Geological and Geochemical Analysis
- Drilling and Well Engineering
- Hydraulic Fracturing and Reservoir Analysis
- Marine and environmental studies
- Reservoir Engineering and Simulation Methods
- Rock Mechanics and Modeling
- CO2 Sequestration and Geologic Interactions
- Landslides and related hazards
- Geotechnical and Geomechanical Engineering
- Geological and Geophysical Studies Worldwide
- Methane Hydrates and Related Phenomena
- Geothermal Energy Systems and Applications
- Geophysical Methods and Applications
- Maritime and Coastal Archaeology
- Geophysics and Sensor Technology
- Anomaly Detection Techniques and Applications
- Hydrocarbon exploration and reservoir analysis
- Geological and Geophysical Studies
- Geochemistry and Geologic Mapping
GFZ Helmholtz Centre for Geosciences
2016-2025
Freie Universität Berlin
2016-2025
Geomechanica (Canada)
2020
University of Potsdam
2012
Stanford University
2009-2010
Universität Hamburg
2001-2004
Ruhr University Bochum
2003-2004
We show that near-real-time seismic monitoring of fluid injection allowed control induced earthquakes during the stimulation a 6.1-km-deep geothermal well near Helsinki, Finland. A total 18,160 m3 fresh water was pumped into crystalline rocks over 49 days in June to July 2018. Seismic performed with 24-station borehole seismometer network. Using information on induced-earthquake rates, locations, magnitudes, and evolution hydraulic energy, pumping either stopped or varied-in latter case,...
Surface roughness ubiquitously prevails in natural faults across various length scales. Despite extensive studies highlighting the important role of fault geometry dynamics tectonic earthquakes, whether and how affects fluid-induced seismicity remains elusive. Here, we investigate effects stress heterogeneity on slip associated characteristics using laboratory experiments numerical modeling. We perform fluid injection quartz-rich sandstone samples containing either a smooth or rough fault....
Combined P and S receiver functions from seismograms of teleseismic events recorded at 65 temporary permanent stations in the Aegean region are used to map geometry subducted African overriding plates. We image Moho subducting plate depths ranging 40 km beneath southern Crete western Peloponnesus 160 volcanic arc 220 northern Greece. However, dip is shallower than Rhodes flattens out Aegean. Observed P‐to‐S conversions located forearc indicate a reversed velocity contrast boundary plate,...
Online Material: Figures of complete stress inversion results. The estimation the stress‐field orientation from focal mechanisms earthquakes is a relevant tool to understand crustal mechanics and physics earthquakes. In global seismology, Formal Stress Inversion (FSI) well‐established technique study tectonic processes associated with occurrence large (e.g., Hardebeck Michael, 2004; Yoshida et al. , 2012). Information on also for exploitation hydrocarbon geothermal reservoirs. Knowledge...
The East Anatolian Fault Zone (EAFZ) represents a plate boundary extending over ∼500 km between the Arabian and plates. Relative motion occurs with slip rates ranging from 6 to 10 mm/yr has resulted in destructive earthquakes eastern Turkey as documented by historical records. In this study, we investigate seismic activity along EAFZ fault kinematics based on recordings densified regional network providing best possible azimuthal coverage for target region. We optimize reference 1‐D velocity...
Large-magnitude fluid-injection induced seismic events are a potential risk for geothermal energy developments worldwide. One mitigation measure is the application of cyclic injection schemes. After validation at small (laboratory) and meso (mine) scale, concept has now been applied first time field scale Pohang Enhanced Geothermal System (EGS) site in Korea. From 7 August until 14 2017 total 1756 m³ surface water was injected into well PX-1 flow rates between 1 10 l s–1, with maximum...
Constraining the maximum likely magnitude of future earthquakes on continental transform faults has fundamental consequences for expected seismic hazard. Since recurrence time those is typically longer than a century, such estimates rely primarily well-documented historical earthquake catalogs, when available. Here we discuss observed magnitudes along different sections North Anatolian Fault Zone (NAFZ) in relation to age fault activity, cumulative offset, slip rate and length coherent...
Abstract The spatiotemporal, kinematic, and source characteristics of induced seismicity occurring at different fluid injection rates are investigated to determine the predominant physical mechanisms responsible for northwestern part Geysers geothermal field, California. We analyze a relocated hypocenter catalog from cluster where significant variations stress tensor orientation were previously observed correlate with rates. find that these changes may be related increased pore pressure...
Research Article| May 11, 2016 HybridMT: A MATLAB/Shell Environment Package for Seismic Moment Tensor Inversion and Refinement Grzegorz Kwiatek; Kwiatek aHelmholtz Centre Potsdam, GFZ German Geosciences, Section 4.2: Geomechanics Rheology, Telegrafenberg, 14473 Germanykwiatek@gfz-potsdam.de Search other works by this author on: GSW Google Scholar Patricia Martínez‐Garzón; Martínez‐Garzón Marco Bohnhoff Seismological Letters (2016) 87 (4): 964–976. https://doi.org/10.1785/0220150251 Article...
Abstract Studying variations of the stress field in reservoirs caused by massive fluid injection is important toward an improved understanding geomechanical processes involved. We report on spatio‐temporal local tensor orientation at The Geysers geothermal field, California. apply two inversion methods with detailed uncertainty assessments using a selection events recorded between 2007 and 2012. Our results clearly indicate principal axes for reservoir as whole showing normal faulting regime...
Abstract Understanding the physical mechanisms governing fluid‐induced fault slip is important for improved mitigation of seismic risks associated with large‐scale fluid injection. We conducted experiments in laboratory on critically stressed saw‐cut sandstone samples high permeability using different pressurization rates. Our experimental results demonstrate that behavior governed by rate rather than injection pressure. Slow stick‐slip episodes (peak velocity < 4 μm/s) are induced fast...
Abstract The long‐term temporal and spatial changes in statistical, source, stress characteristics of one cluster induced seismicity recorded at Geysers geothermal field (U.S.) are analyzed relation to the operations, fluid migration, constraints on maximum likely magnitude. Two injection wells, Prati‐9 Prati‐29, located northwestern part their associated composed 1776 events throughout a 7 year period were analyzed. catalog was relocated, source including focal mechanisms static parameters...
Abstract We develop an improved methodology for reliable high‐resolution inversions of focal mechanisms to background stress field orientation and ratio R in two or three dimensions. The earthquake catalog is declustered remove events likely affected strongly by local interactions rather than reflecting the large‐scale field. data are discretized with k ‐means algorithm into groups containing a number between minimum N min 2 . Synthetic tests indicate that ≈ 30 provides stable inversion...
Abstract Small stress changes such as those from sea level fluctuations can be large enough to trigger earthquakes. If small and earthquakes initiate similarly, high‐resolution catalogs with low detection thresholds are best suited illuminate processes. Below the Sea of Marmara section North Anatolian Fault, a segment 150 km is late in its seismic cycle. We generated seismicity for hydrothermal region eastern employing AI‐based template matching techniques investigate link between over 6...
Abstract We discuss data of three laboratory stick‐slip experiments on Westerly Granite samples performed at elevated confining pressure and constant displacement rate rough fracture surfaces. The produced complex slip patterns including fast slow ruptures with large small fault slips, as well failure events the surface producing acoustic emission bursts without externally‐detectable stress drop. Preparatory processes leading to slips were tracked an ensemble ten seismo‐mechanical...
Abstract We investigate source processes of fluid‐induced seismicity from The Geysers geothermal reservoir in California to determine their relation with hydraulic operations and improve the corresponding seismic hazard estimates. Analysis 869 well‐constrained full moment tensors ( M w 0.8–3.5) reveals significant non‐double‐couple components (>25%) for about 65% events. Volumetric deformation is governed by cumulative injection rates larger observed near wells during high periods. Source...
We perform a detailed synthetic study on the resolution of non-double-couple (non-DC) components in seismic moment tensors from short-period data observed at regional networks designed typically for monitoring aftershock sequences large earthquakes. In addition, we test two different inversion approaches—a linear full tensor and non-linear constrained to shear-tensile source model. The inversions are applied first-motion P- S-wave amplitudes, which mimic observations aftershocks 1999 Mw =...
Short term prediction of earthquake magnitude, time, and location is currently not possible. In some cases, however, documented observations have been retrospectively considered as precursory. Here we present seismicity transients starting approx. 8 months before the 2023 MW 7.8 Kahramanmaraş on East Anatolian Fault Zone. Seismicity composed isolated spatio-temporal clusters within 65 km future epicentre, displaying non-Poissonian inter-event time statistics, magnitude correlations low...
Recently, Machine learning (ML) has been widely utilized for laboratory earthquake (labquake) prediction using various types of data. This study pioneers in time to failure (TTF) based on ML acoustic emission (AE) records from three stick-slip experiments performed Westerly granite samples with naturally fractured rough faults, more similar the heterogeneous fault structures nature. 47 catalog-driven seismo-mechanical and statistical features are extracted introducing some new focal...
SUMMARY Earthquake forecasting poses significant challenges, especially due to the elusive nature of stress states in fault systems. To tackle this problem, we use features derived from seismic catalogues obtained acoustic emission (AE) signals recorded during triaxial stick-slip experiments on natural fractures three Westerly granite samples. We extracted 47 physically explainable AE data that described spatio-temporal evolution and damage vicinity surface. These are then subjected...
Urban areas are very vulnerable to the effects of geohazards, with a high potential for human life and financial loss due their population density advanced infrastructure. Obtaining high-resolution, subsurface information in urban is critical understand mitigate these hazards. In densely populated centers, shallow Earth most stressed, as activities continuously change properties interfere natural processes. Geophysical surveys often face limitations environments logistical constraints...