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Masfara, La ODE Marzujriban (author), Weemstra, C. (author)The Hamiltonian Monte Carlo algorithm is known to be highly efficient when sampling high-dimensional model spaces due to Hamilton's equations guiding the sampling process. For weakly non-linear problems, linearizing the forward problem enhances this efficiency. This study integrates this linearization with geological prior knowledge for...journal article 2024
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Naranjo, D. (author), Parisi, Laura (author), Jónsson, Sigurjón (author), Jousset, Philippe (author), Werthmüller, D. (author), Weemstra, C. (author)Ocean-bottom seismometers (OBSs) are equipped with seismic sensors that record acoustic and seismic events at the seafloor, which makes them suitable for investigating tectonic structures capable of generating earthquakes offshore. One critical parameter to obtain accurate earthquake locations is the absolute time of the incoming seismic signals...journal article 2024
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Kettlety, T. (author), Martuganova, E.M. (author), Kühn, D. (author), Schweitzer, J. (author), Weemstra, C. (author), Baptie, B. (author), Dahl-Jensen, T. (author), Kendall, J.M. (author)With the development of several CO₂ storage operations in the North Sea, there is a clear need to better characterise the seismic hazard and stress state in the region. Faults and associated fracture sets can act as hydraulic pathways for unintended CO₂ migration, ill-defined stress states can lead to numerous operational difficulties, and...conference paper 2023
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Rahimi Dalkhani, A. (author), Áústsdóttir, Thorbjörg (author), Gudnason, Egill Árni (author), Hersir, Gylfi Páll (author), Zhang, Xin (author), Weemstra, C. (author)Ambient noise seismic tomography has proven to be an effective tool for subsurface imaging, particularly in volcanic regions such as the Reykjanes Peninsula (RP), SW Iceland, where ambient seismic noise is ideal with isotropic illumination. The primary purpose of this study is to obtain a reliable shear wave velocity model of the RP, to get a...journal article 2023
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Cheng, H. (author), Weemstra, C. (author), Hendriks, M.A.N. (author), Yang, Y. (author)Coda wave interferometry (CWI) holds promise as a technique for concrete stress monitoring. This is because the coda, which consists of multiply scattered arrivals, is the result of propagation through the medium over large distances. As such, it is sensitive to both minute structural changes and small velocity changes in that medium....journal article 2023
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Naranjo, D. (author), Parisi, Laura (author), Jónsson, Sigurjón (author), Jousset, Philippe (author), Werthmüller, D. (author), Weemstra, C. (author)The timing of the recordings of ocean-bottom seismometers (OBSs) is critical for accurate earthquake location and Earth model studies. GNSS signals, however, cannot reach OBSs deployed at the ocean bottom. This prevents their clocks from being synchronized with a known reference time. To overcome this, we developed OCloC, a Python package that...abstract 2023
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Weemstra, C. (author), Rahimi Dalkhani, A. (author), Ágústsdóttir, Þorbjörg (author), Guðnason, Egill Árni (author), Hersir, Gylfi Páll (author), Zhang, Xin (author)We report on a Bayesian (i.e., probabilistic) inversion for the shear-wave velocity structure of the Reykjanes peninsula, SW Iceland. Travel times of Rayleigh waves traversing the peninsula served as input to the probabilistic algorithm. These Rayleigh waves were retrieved through the application of seismic interferometry to yearlong recordings...abstract 2023
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Draganov, D.S. (author), Naranjo, D. (author), Polychronopoulou, Katerina (author), Weemstra, C. (author)Geothermal energy is a cleaner and more sustainable source of power, which plays a key role in the transition to a low-carbon economy. Sustainable and safe exploitation of geothermal resources, however, depends on our ability to understand and manage the associated seismic risks. In 2018, Nature's Heat geothermal project began operations in...abstract 2023
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Masfara, La ODE Marzujriban (author), Cullison, Thomas (author), Weemstra, C. (author)We present an efficient probabilistic workflow for the estimation of source parameters of induced seismic events in three-dimensional heterogeneous media. Our workflow exploits a linearized variant of the Hamiltonian Monte Carlo (HMC) algorithm. Compared to traditional Markov chain Monte Carlo (MCMC) algorithms, HMC is highly efficient in...journal article 2022
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Naranjo, D. (author), Draganov, D.S. (author), Weemstra, C. (author)In 2018, a geothermal doublet started operating in Kwinstheul, Netherlands, for supplying heat to 64 hectares of greenhouses corresponding to Nature’s Heat joint initiative. This kind of geothermal operation requires extraction, circulation, and reinjection of fluids at a depth of 2.4 km. The reservoir used for the geothermal operation has shown...abstract 2022
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Smets, P.S.M. (author), Weemstra, C. (author), Evers, L.G. (author)We report on the extraction of deep ocean travel time variations from time-lapse cross-correlations between a hydrophone station and a three-component broadband seismometer. The signals we cross-correlate in this study result from repeated activity by the Monowai seamount, one of the most active submarine volcanoes of the Tonga-Kermadec ridge...journal article 2022
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Naranjo, D. (author), Draganov, D.S. (author), Polychronopoulou, Katerina (author), De Bas, Mathieu (author), Weemstra, C. (author)In 2018, the geothermal project Nature's Heat started its operations to supply heat to 64 hectares of greenhouses in Kwintsheul, Netherlands. The operation involves the extraction and reinjection of geothermal fluids at a depth of about 2.4km. Several studies suggested that geothermal operations in these parts of The Netherlands are unlikely to...conference paper 2022
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Muntendam-Bos, A.G. (author), Hoedeman, Gerco (author), Polychronopoulou, Katerina (author), Draganov, D.S. (author), Weemstra, C. (author), van der Zee, Wouter (author), Bakker, R.R. (author), Roest, J.C. (author)We present an overview of induced seismicity due to subsurface engineering in the Netherlands. Our overview includes events induced by gas extraction, underground gas storage, geothermal heat extraction, salt solution mining and post-mining water ingress. Compared to natural seismicity, induced events are usually small (magnitudes ≤ 4.0)....journal article 2022
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Naranjo, D. (author), Parisi, Laura (author), Jousset, Philippe (author), Weemstra, C. (author), Jónsson, Sigurjón (author)Accurate timing of seismic records is essential for almost all applications in seismology. Wrong timing of the waveforms may result in incorrect Earth models and/or inaccurate earthquake locations. As such, it may render interpretations of underground processes incorrect. Ocean bottom seismometers (OBSs) experience clock drifts due to their...abstract 2021
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Rahimi Dalkhani, A. (author), Zhang, Xin (author), Weemstra, C. (author)Seismic travel time tomography using surface waves is an effective tool for three-dimensional crustal imaging. Historically, these surface waves are the result of active seismic sources or earthquakes. More recently, however, surface waves retrieved through the application of seismic interferometry have also been exploited. Conventionally, two...journal article 2021
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Shirmohammadi, F. (author), Draganov, D.S. (author), Hatami, Mohammad Reza (author), Weemstra, C. (author)Seismic interferometry (SI) refers to the principle of generating new seismic responses using crosscorrelations of existing wavefield recordings. In this study, we report on the use of a specific interferometric approach, called seismic interferometry by multidimensional deconvolution (SI by MDD), for the purpose of retrieving surface-wave...journal article 2021
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Weemstra, C. (author), De Laat, Janneke I. (author), Verdel, Arie (author), Smets, P.S.M. (author)Instrumental timing and phase errors are a notorious problem in seismic data acquisition and processing. These can be frequency independent, for example due to clock drift, but may also be frequency dependent, for example due to imperfectly known instrument responses. A technique is presented that allows both types of errors to be recovered...journal article 2020
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- Shirmohammadi, F. (author), Weemstra, C. (author), Draganov, D.S. (author), Wapenaar, C.P.A. (author) poster 2019
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van IJsseldijk, J.E. (author), Ruigrok, Elmer (author), Verdel, Arie (author), Weemstra, C. (author)Global phases, viz. seismic phases that travel through the Earth?s core, can be used to locally image the crust by means of seismic interferometry. This method is known as Global Phase Seismic Interferometry (GloPSI). Traditionally, GloPSI retrieves low-frequency information (up to 1 Hz). Recent studies, however, suggest that there is high...journal article 2019
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Martins, Joana E. (author), Weemstra, C. (author), Ruigrok, Elmer (author), Verdel, Arie (author), Jousset, Philippe (author), Hersir, Gylfi (author)Tomographic imaging based on ambient seismic noise measurements has shown to be a powerful tool, especially in areas like Iceland, where the microseism illumination is excellent. In this paper, we produce a 3D S-wave tomographic image over the western Reykjanes Peninsula high-enthalpy geothermal fields and evaluate the reliability of the...journal article 2019