A5064901208- Seismic Imaging and Inversion Techniques
- Seismic Waves and Analysis
- Seismology and Earthquake Studies
- earthquake and tectonic studies
- CO2 Sequestration and Geologic Interactions
- Hydraulic Fracturing and Reservoir Analysis
- Drilling and Well Engineering
- Reservoir Engineering and Simulation Methods
- Rock Mechanics and Modeling
- Earthquake Detection and Analysis
- Geological Modeling and Analysis
- High-pressure geophysics and materials
- Geophysics and Sensor Technology
- Landslides and related hazards
- Hydrocarbon exploration and reservoir analysis
- Geophysical Methods and Applications
- Advanced Fiber Optic Sensors
- Geotechnical and Geomechanical Engineering
- Anomaly Detection Techniques and Applications
- 3D Surveying and Cultural Heritage
- Methane Hydrates and Related Phenomena
- Underwater Acoustics Research
- Dam Engineering and Safety
- Geophysical and Geoelectrical Methods
- Infrastructure Maintenance and Monitoring
Norsar
2016-2025
University of Oslo
2017-2025
Norwegian University of Science and Technology
2023
Equinor (United Kingdom)
2018
Norwegian Geotechnical Institute
2010
Norsk Hydro (Norway)
2005
Abstract Distributed acoustic sensing (DAS) can be deployed on existing submarine fiber-optic cables to add long-range sensor capability the cable infrastructure. In this article, we present following: (1) observations and analysis of impulsive source events from long-term DAS measurements a North Sea telecommunications cable. The include local earthquakes originating in crust below cable, underwater explosions water column, an onshore explosion nearby coast, examples sonic booms supersonic...
Most earthquake location methods require phase identification and arrival-time measurements. These are generally fast efficient but not always applicable to microearthquake data with low signal-to-noise ratios because the might be very difficult. The migration-based source methods, which do an explicit identification, often more suitable for such noisy data. Whereas some existing computationally intensive, others limited a certain type of or make use only particular signal. We have developed...
We present results from microseismic monitoring and geomechanical analysis obtained at the industrial-scale CO2 sequestration site In Salah gas development project in Algeria. More than 5000 events have been detected a pilot well using master event cross-correlation method. The activity occurs four distinct clusters thereof three clearly correlate with injection rates wellhead pressures. These are consistent location within reservoir interval. However, due to insufficient network geometry...
Abstract microseismicity induced by CO 2 injection at Decatur, Illinois, occurs in distinct clusters and shows no obvious correlation with the proceeding pressure front. We analyze some of these more depth using a waveform cross‐correlation approach. With this approach we can associate about 1400 events from two clusters, moment magnitudes between 1.1 −1.7, specific formations much smaller vertical dimensions (tens meters) than resolution traveltime‐based event locations. The differentiation...
ABSTRACT The results of monitoring carbon dioxide (CO2) injection at the Illinois Basin—Decatur Project (IBDP) and companion Industrial Carbon Capture Sequestration Sources (IL-ICCS) project—have shown that reservoir response to fluid pressure changes can vary significantly different locations within same reservoir. Predrill characterization is important identify potentially seismogenic faults. However, interpretations newly reprocessed 3D seismic reflection data illustrate challenges...
Abstract Distributed Acoustic Sensing (DAS) involves the transmission of laser pulses along a fiber‐optic cable. These are backscattered at fiber inhomogeneities and again detected by same interrogator unit that emits pulses. Elastic deformation causes phase shifts in which converted to spatially averaged strain measurements, typically regular intervals. DAS systems provide potential employ array processing algorithms. However, there certain differences between conventional sensors. While...
To investigate source-scaling relations for small earthquakes (M{sub w} -1.8 to 1.2) we have determined source parameters numerous events ({approx}1500) from the 1400-m-deep Pyhasalmi ore mine in Finland. In addition a spectral integration approach, fitted Brune, Boatwright, and Haskell spectral-shape models observed spectra investigated attenuation influences. Of three different constant Q (200, 350, 800), of 350 combination with Brune model satisfied data best. We also frequency dependence...
Microseismic data analysis together with interpretation of injection at the In Salah CO2 storage site provides a valuable tool for improved understanding subsurface and processes. More than 1500 microseismic events have been detected semi-automatically between August 2009 May 2012 occurrence correlates clearly increased rates well-head pressures. Most likely fracture pressure has exceeded temporarily, resulting in sudden increase microseismicity. Waveform cross- correlation demonstrates that...
Climate change is impacting the Arctic faster than anywhere else in world. As a response, ecosystems are rapidly changing. result, we can expect rapid shifts whale migration and habitat use concurrent with changes human patterns. In this context, responsible management conservation requires improved monitoring of presence movement over large ranges, at fine scales near-real-time compared to legacy tools. We demonstrate that could be enabled by Distributed Acoustic Sensing (DAS). DAS converts...
Microseismic monitoring forms part of the active risk management system in a well-run CO2 storage project. Apart from providing input to and assessment seismic hazard within around formation, potentially mitigation via real-time warning system, microseismic event data can be used for reservoir characterization optimization injection operations. This study compares various sensor technologies at Quest CCS site Alberta, Canada where network includes downhole geophones, distributed acoustic...
Abstract We document a complete seismic hazard study for mainland Norway and the Svalbard archipelago. The is based on Probabilistic Seismic Hazard Analysis (PSHA) method, first time new earthquake catalogue presented publicly that covers Norway, adjacent offshore regions. developed from an extensive analysis of historical earthquakes combined with more recent instrumental data 33,864 reports between 1497 through 2018, magnitudes up to Mw 6.7. With this computed 10% exceedance in 475 years...
<title>Abstract</title> Effectively presenting seismic risk results is crucial for ensuring that stakeholders, including policymakers and first-responders can understand utilize the information decision-making mitigation. In this study, we conducted a comprehensive assessment Oslo (capital of Norway), integrating both deterministic probabilistic approaches to capture holistic view potential earthquake impacts. Based on field data from exposed major faults in rift margin historical...
Abstract Pausing injection and production can lead to induced seismicity in a variety of settings, with some the largest events occurring during these so-called shut-ins. In geothermal fields, shut-ins are periodically conducted for maintenance wells surface infrastructure, thereby offering recurring means estimating stress changes subsurface that increased rates. Here, we examine daily microseismicity data from Coso field (CGF) California between 1996 2010 investigate repetitive trends...
Abstract Spectral analysis (SA) for image processing, utilizing the Fast Fourier Transform (FFT), computes 2D power spectrum to capture amplitude of each frequency component an image. Recent studies have applied SA on digital elevation models (DEMs) characterize repetitive and spatially homogeneous landforms in terms their orientation, frequency, amplitude. Here, we advance application by introducing a new preprocessing step appropriate windowing function, tailored analyze heterogenous...
SUMMARY In this paper, we present a catalogue of relocated seismic events in the North Sea spanning 1961 to 2022. Data from all relevant agencies were combined, incorporating available phase readings, thereby enhancing station coverage. As result, our updated locations reveal more clustered and aligned seismicity pattern compared with original catalogue. Even combined data set, only 157 7089 have azimuthal gaps less than 90 deg. Additionally, distances between onshore stations offshore are...
The &#197;knes rockslide is located on the slope of a steeply dipping fjord in Norway proximity urban areas, posing significant hazard due to its potential trigger massive tsunami. This study utilizes data from eight vertically aligned borehole geophones and one broadband seismometer surface, collected over period approximately 22 months. Previous research has demonstrated that passive seismic monitoring, specifically tracking changes velocities, can provide precursory indicators...
SUMMARY We implement a spectral‐element method for 3D time‐independent elastoplastic problems in geomechanics. As first application, we use the slope stability analyses ranging from small to large scales. The implementation employs an element‐by‐element preconditioned conjugate‐gradient solver efficient storage. program accommodates material heterogeneity and complex topography. Either simple or water table profiles may be used assess effects of hydrostatic pressure. Both surface loading...
A priori assessment of the expected location accuracy a sensor network is typically done through inversion traveltime spatial gradients. This approach assumes that applied algorithm successfully recovers global minimum objective function. However, even for accurate and precise phase picks, complexity in velocity model limitations layout may inhibit finding minimum. The algorithms end up local instead. We compare performance various functions minimization approaches. Although most analyzed...