A5025189776- Seismic Waves and Analysis
- Seismology and Earthquake Studies
- Advanced Fiber Optic Sensors
- earthquake and tectonic studies
- Geophysics and Sensor Technology
- Seismic Imaging and Inversion Techniques
- Drilling and Well Engineering
- High-pressure geophysics and materials
- Earthquake Detection and Analysis
- Micro and Nano Robotics
- Nonlinear Dynamics and Pattern Formation
- Marine and environmental studies
- Geophysical Methods and Applications
- Reservoir Engineering and Simulation Methods
- Microfluidic and Bio-sensing Technologies
- Structural Health Monitoring Techniques
- Hydraulic Fracturing and Reservoir Analysis
- Geological Formations and Processes Exploration
- Underwater Vehicles and Communication Systems
- Optical measurement and interference techniques
- Methane Hydrates and Related Phenomena
- Geographic Information Systems Studies
- Geochemistry and Geologic Mapping
- Advanced Surface Polishing Techniques
- Advanced Thermodynamics and Statistical Mechanics
GFZ Helmholtz Centre for Geosciences
2018-2024
Technische Universität Berlin
2010-2011
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,...
Hair-like appendages called cilia on the surface of a microorganism such as Paramecium or Opalina beat highly synchronized and form so-called metachronal waves that travel along surfaces. In order to study under what principal conditions these form, we introduce chain beads, rowers, each periodically driven by an external force straight line segment. To implement hydrodynamic interactions between they are considered point-like. Two beads synchronize in antiphase phase depending positive...
Discriminating between a creeping and locked status of active faults is central relevance to characterize potential rupture scenarios future earthquakes the associated seismic hazard for nearby population centres. In this respect, highly similar that repeatedly activate same patch an fault portion are important diagnostic tool identify possibly even quantify amount creep. Here, we present refined hypocentre catalogue Marmara region in northwestern Turkey, where magnitude M up 7.4 earthquake...
Geothermal productivity strongly depends on reservoir performance, which is regularly monitored. This work presents the results from Distributed Dynamic Strain Sensing (DDSS or DAS) measurements during restart of injection and production in deep geothermal wells. technology's high spatiotemporal resolution enables monitoring relative strain temperature changes along entire sensing cable. We monitored 3.7 km a producer approximately 4.1 an injector. Both cables were installed post-borehole...
Distributed Acoustic Sensing (DAS) technology can convert unused fiber-optic cables of existing telecommunication networks (dark fibers) into arrays virtual seismic receivers. Moreover, the waves generated by human activities recorded on these receiver be used to seismically image urban subsurface at high resolution with a small footprint. This capability help evaluate potential for safe and sustainable utilization in numerous applications, such as groundwater management also geothermal...
Understanding volcanic processes is fundamental for anticipating impacts of eruptive activity on human activities and environment. Deformation seismicity often precede accompany eruptions. Models magma emplacement ground deformation associated with eruptions are obtained from GNSS InSAR observations seismic source mechanisms observations. While satellite sensing techniques benefit a large spatial coverage but coarse temporal resolution accuracy (mm range), seismometer networks acquire dense...
Residues of industrial mining activities like rock waste, tailings, and stockpiles are amongst the largest human-made structures in both area volume. In case tailings dams, risk posed by failure is well documented has led to implementation regulatory standards. As one measures reduce potential harm environment people, Global Industry Standard on Tailings Managment (GISTM) implemented UNEP 2020 proposes installation "monitoring systems manage at all phases facility lifecycle". This objectives...
Achieving well integrity is mandatory for a geothermal well's safe and sustainable operation. One of the most critical steps success primary cementing. Conventional monitoring only shows discrete snapshots after completion cement job. However, optical fiber sensors enable entire cementing process. Here, we investigate placement early hydration surface casing at site in Munich, Germany. We show that distributed dynamic strain rate sensing (DDSS or DAS) allows tracking rising fluid interfaces,...
Abstract We analyze the spatiotemporal evolution of seismicity during a sequence moderate (an Mw 4.7 foreshock and 5.8 mainshock) earthquakes occurring in September 2019 at transition between creeping locked segment North Anatolian fault central Sea Marmara, northwest Turkey. To investigate detail evolution, we apply matched-filter technique to continuous waveforms, thus reducing magnitude threshold for detection. Sequences foreshocks preceding two largest events are clearly seen, exhibiting...
Abstract Strain energy from tectonic loading can be partly released through aseismic creep. Earthquake repeaters, repeatedly activated brittle fault patches surrounded by creep, indicate steady‐state creep that affects the amount of seismic available for next large earthquake along a plate contact. The offshore Main Marmara Fault (MMF) North Anatolian Zone represents gap capable generating M > 7 in direct vicinity to mega‐city Istanbul. Based on newly compiled seismicity catalog, we...
Abstract During February 2023, a total of 32 individual distributed acoustic sensing (DAS) systems acted jointly as global seismic monitoring network. The aim this Global DAS Month campaign was to coordinate diverse network organizations, instruments, and file formats gain knowledge move toward the next generation earthquake networks. campaign, 156 earthquakes magnitude 5 or larger were reported by U.S. Geological Survey contributors shared data for 60 min after each event’s origin time....
Distributed Dynamic Strain Sensing (DDSS), also known as Acoustic (DAS), is becoming a popular tool in array seismology. A new generation of engineered fibers being developed to improve sensitivity and reduce the noise floor comparison standard fibers, which are conventionally used telecommunication networks. Nevertheless, already have extensive coverage around Earth's surface, so it motivates use existing infrastructure DDSS surveys avoid costs logistics. In this study, we compare data from...
Continuous monitoring of volcanic gas emissions is crucial for understanding activity and potential eruptions. However, gases underwater are infrequently studied or quantified. This study explores the Distributed Acoustic Sensing (DAS) technology to monitor degassing. DAS converts fiber-optic cables into high-resolution vibration recording arrays, providing measurements at unprecedented spatio-temporal resolution. We conducted an experiment Laacher See volcano in Germany, immersing a cable...
Abstract From June to August 2021, we deployed a dense seismic nodal network across the Hengill geothermal area in southwest Iceland image and characterize faults high-temperature zones at high resolution. The comprised 498 geophone nodes spread northern Nesjavellir southern Hverahlíð fields was complemented by an existing permanent temporary backbone of total 44 short-period broadband stations. In addition, recorded distributed acoustic sensing data along two fiber optic telecommunication...
SUMMARY Ambient noise tomography on the basis of distributed acoustic sensing (DAS) deployed existing telecommunication networks provides an opportunity to image urban subsurface at regional scales and high-resolution. This capability has important implications in assessment subsurface’s potential for sustainable safe utilization, such as geothermal development. However, extracting coherent seismic signals from DAS ambient wavefield environments low cost remains a challenge. One obstacle is...
In this study we derive the stress tensor and its local variations throughout Marmara region, Turkey. Based on a recently compiled 10-year earthquake catalogue, directly invert first-motion polarity data quantify confidence intervals for principal orientations. We find combined strike-slip normal faulting field region generally reflecting overall transtensional setting. However, results clearly show moderate of field. The largest ( $$\sigma _1$$ ) intermediate _2$$ stresses an average...
Abstract. Fiber-optic distributed acoustic sensing (DAS) data find many applications in wellbore monitoring such as flow monitoring, formation evaluation and well integrity studies. For horizontal or highly deviated wells, fiber-optic installations can be conducted by mounting the cable to a rigid structure (casing/tubing) which allows for controlled landing of cable. We analyze cold-water injection phase geothermal with 3.6 km long installation mounted 3/4 in. sucker rod using both DAS...
Abstract A common challenge in acoustic meteoroid signal analyses is to discriminate whether the observed wavefield can be better described by line-source or point-source models. This typically arises from a sparse availability of observations. In this work, we present an outstanding record ground-coupled waves local large-N seismic and distributed sensing (DAS) observations Iceland. Our complete data set includes additional regional stations located within 300 km meteoroid’s trajectory. The...
Reliable well completion technologies are mandatory for the safe and sustainable use of subsurface reservoirs. Achieving integrity requires displacing entire drilling mud with homogenous cement. For this purpose, surface pump parameters (rate, density, pressure, volume) generally measured, yielding average values along borehole. Here, distributed fiber-optic sensing offers new continuous monitoring options dense spatial sampling within a In GFK-monitor project (https://gfk-monitor.de/en/),...
Ambient noise tomography Derived from Distributed Acoustic Sensing (DAS) deployed on existing telecommunication networks provides an opportunity to image the urban subsurface at local regional scales and high resolution effectively with a small footprint. This capability can contribute assessment of subsurface's potential for sustainable safe utilization in countless applications, such as geothermal development area. However, extracting coherent seismic signals DAS ambient wavefield...
In the last 5 years, seismological community has experienced an impressive growth in novel Distributed Acoustic Sensing (DAS) technique, terms of both number experiments and generated data volume. DAS can generate at a much finer resolution space time, than is seen with standard acquisition techniques. This creates challenges not only for centres regarding management, but also users that need to access process this data. The current standards metadata formats, as well services...
Monitoring of seismic activity around volcanoes has been conventionally performed using data from continuous and deformation networks, which give real-time information on the status a volcano at any time. In case volcanic crisis, number earthquakes often increases with time conventional networks are completed by deployment additional sensors, allow for better hazard assessment, e.g., lowering detection threshold improving earthquake locations. The such sensors is labour intensive may be...
This chapter describes fiber optic sensing methodologies and their applications for understanding volcanic structure processes. We assess benefits volcano monitoring offer possible solutions to address challenges. The physical principles at the basis of technologies have been known several decades. These are related various processes involving electro-magnetic interactions light sent by a laser within glass. Intrinsic properties glass optical fiber, when engineered appropriately interrogated...