Seismological Research Letters最新文献

{"title":"Nominations for the Next Joyner Lecturer Due 30 June","authors":"","doi":"10.1785/0220240178","DOIUrl":"https://doi.org/10.1785/0220240178","url":null,"abstract":"It is time to submit nominations for the 2025 William B. Joyner Memorial Lecturer. Established by SSA in cooperation with the Earthquake Engineering Research Institute (EERI), these lectures honor Bill Joyner’s distinguished career at the U.S. Geological Survey and his abiding commitment to the exchange of information at the interface of earthquake science and earthquake engineering.Joyner Lecturers are chosen on the basis of their work at this interface, whether it involves contributions from earthquake science to earthquake engineering, or from earthquake engineering to earthquake science. Nominations can be made by any member of EERI or SSA, and the lecturer...","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"27 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Follow the Trace: Becoming a Seismo‐Detective with a Campus‐Based Raspberry Shake Seismometer","authors":"Eric Löberich, Maureen D. Long","doi":"10.1785/0220230365","DOIUrl":"https://doi.org/10.1785/0220230365","url":null,"abstract":"Seismic signals, whether caused by earthquakes, other natural phenomena, or artificial noise sources, have specific characteristics in the time and frequency domains that contain crucial information reflecting their source. The analysis of seismic time series is an essential part of every seismology‐oriented study program. Enabling students to work with data collected from their own campus, including signals from both anthropogenic and natural seismic sources, can provide vivid, practical examples to make abstract concepts communicated in classes more concrete and relevant. Data from research‐grade broadband seismometers enable us to record time series of vibrations at a broad range of frequencies; however, these sensors are costly and are often deployed in remote places. Participation in the Raspberry Shake citizen science network enables seismology educators to record seismic signals on our own campuses and use these recordings in our classrooms and for public outreach. Yale University installed a Raspberry Shake three‐component, low‐cost seismometer in the Earth and Planetary Sciences department building in Summer 2022, enabling the detection of local, regional, and teleseismic earthquakes, microseismic noise, and anthropogenic noise sources from building construction, an explosive event in a steam tunnel, and general building use. Here, we discuss and illustrate the use of data from our Raspberry Shake in outreach and education activities at Yale. In particular, we highlight a series of ObsPy‐based exercises that will be used in courses taught in our department, including our upper‐level Introduction to Seismology course and our undergraduate classes on Natural Disasters and Forensic Geoscience.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"119 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microseismic Event Location with Dual Vertical DAS Arrays: Insights from the FORGE 2022 Stimulation","authors":"Eyal Shimony, Ariel Lellouch","doi":"10.1785/0220230128","DOIUrl":"https://doi.org/10.1785/0220230128","url":null,"abstract":"We investigate the resolvability of a microseismic event location given a recording array composed of vertical distributed acoustic sensing (DAS) boreholes. We use a modified source‐scanning algorithm that takes into account both P and S waves. We transform the brightness maps it produces into probability density functions (PDFs), over which we carry out a resolution and uncertainty analysis. We apply this approach to microseismic events recorded by two vertical DAS boreholes as part of the Frontier Observatory for Research in Geothermal Energy (FORGE) project. We show that for the specific acquisition geometry in FORGE, the horizontal location of the events cannot be determined, but their depth can, similar to results obtained with a single borehole. Using synthetic examples, we show that the recording array’s geometry is the limiting factor in the determination of the horizontal location. We investigate various possible recording geometries composed of idealized DAS‐like vertical boreholes with varying locations and depths. We find that, besides the number of recordingd boreholes, their depth is the main factor influencing the location estimation uncertainty. The number and position of the boreholes mainly influence the spatial distribution of the PDF, whereas the boreholes’ depth mainly influences its size. Despite the simplicity of our analysis, it highlights the influence of the monitoring array design for microseismic events’ locating using vertical DAS arrays.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"225 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Empirical Source‐Scaling Laws for Crustal Earthquakes Incorporating Fault Dip and Seismogenic‐Thickness Effects","authors":"Jyun‐Yan Huang, Norman A. Abrahamson, Chih‐Hsuan Sung, Shu‐Hsien Chao","doi":"10.1785/0220240034","DOIUrl":"https://doi.org/10.1785/0220240034","url":null,"abstract":"New global source‐scaling relations for the aspect ratio and rupture area for crustal earthquakes that include the width‐limited effect and a possible free‐surface effect are derived using a global dataset of finite‐fault rupture models. In contrast to the commonly used scaling relations between moment magnitude (M), fault length (L), width (W), and area, we built self‐consistent scaling relations by relating M to the aspect ratio (L/W) and to the fault area to model the change in the aspect ratio once the rupture width reaches the down‐dip width limit of the fault. The width‐limited effect of large‐magnitude earthquakes depends on the fault dip and a regional term for the seismogenic thickness. The magnitude scaling of the aspect ratio includes a break in the magnitude scaling that is dip angle dependent. This dip angle‐dependent magnitude scaling in the magnitude–area relation is modeled by a trilinear relation incorporating a dip‐related transition range. The effect of the free surface was observed using a normalized depth term and parameterizing the source by the depth of the top of the fault rupture; it is more apparent in the area scaling relation. The scaling differences are related to the fault geometry, not to the rake angle, as commonly assumed. Finally, the corresponding L and W scaling relations obtained by converting the area and aspect ratio models to L and W models not only show good agreement with the previous regional scaling laws on average but also provide better fault‐specific application due to the inclusion of a fault‐specific dip angle and seismogenic thickness.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"30 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Imaging Urban Hidden Faults with Ambient Noise Recorded by Dense Seismic Arrays","authors":"Ettore Biondi, Jorge C. Castellanos, Robert W. Clayton","doi":"10.1785/0220230408","DOIUrl":"https://doi.org/10.1785/0220230408","url":null,"abstract":"The identification of preexisting near‐surface faults represents a piece of crucial information needed to correctly assess the seismic hazard of any area. The mapping of these structures is particularly challenging in densely populated and heavily urbanized areas. We use ambient seismic noise recorded by a dense array in Seal Beach, California, to image shallow fault lines via a reflected surface‐wave analysis. Our results highlight the presence of previously unknown shallow faults that correlate remarkably well with shallow seismicity and active survey images.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"216 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrology Drives Crustal Deformation and Modulates Seismicity in the Matese Massif (Italy)","authors":"Francesco Pintori, Federica Sparacino, Federica Riguzzi","doi":"10.1785/0220230239","DOIUrl":"https://doi.org/10.1785/0220230239","url":null,"abstract":"We analyze the interplay between hydrology, deformation, and seismicity in the Matese massif, located in the Italian Southern Apennines. We find that this area is characterized by the concurrent action of two hydrologically driven processes: the first is the deformation detected by the Global Navigation Satellite Systems (GNSS) data in the shallowest part (above the elevation of the major springs) of the Earth crust, in phase with the hydrological forcing; the second is the triggering of seismicity at depth with a delay suggesting a downward diffusive process. We study the first process by applying a principal component analysis to the GNSS displacements time series, aiming to identify a common signal describing the largest data variance. We find that the maximum horizontal displacements associated with the first principal component (PC1) are larger than 1 cm in two GNSS sites, and the PC1 temporal evolution is well correlated and in phase with the flow of the largest spring of the region, which we consider as proxy of the water content of the massif. This suggests that the main source of horizontal deformation is the water content fluctuations in the shallow portion of the Matese aquifer, in particular within fractures located in correspondence of the main mapped faults. The deformation rates caused by this process are one order of magnitude larger than the tectonic ones. Finally, we infer the second process by observing the correlation between the background seismicity and the spring discharge with a time lag of 121 days. In our interpretation, downward diffusive processes, driven by aquifer water content variations, propagate pore‐pressure waves that affect the fault’s strength favoring the occurrence of microearthquakes. This is supported by the values of hydraulic diffusivity (⁠1.5 m2/s⁠) and rock permeability (⁠3.2–3.8×10−13 m2⁠), which are compatible with what is observed in karstified limestones.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"19 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140803271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ensemble Region‐Specific GMMs for Subduction Earthquakes","authors":"Farhad Sedaghati, Shahram Pezeshk","doi":"10.1785/0220230070","DOIUrl":"https://doi.org/10.1785/0220230070","url":null,"abstract":"This study develops data‐driven global and region‐specific ground‐motion models (GMMs) for subduction earthquakes using a weighted average ensemble model to combine four different nonparametric supervised machine‐learning (ML) algorithms, including an artificial neural network, a kernel ridge regressor, a random forest regressor, and a support vector regressor. To achieve this goal, we train individual models using a subset of the Next Generation Attenuation‐Subduction (NGA‐Sub) data set, including 9559 recordings out of 153 interface and intraslab earthquakes recorded at 3202 different stations. A grid search is used to find each model’s best hyperparameters. Then, we use an equally weighted average ensemble approach to combine these four models. Ensemble modeling is a technique that combines the strengths of multiple ML algorithms to mitigate their weaknesses. The ensemble model considers moment magnitude (M), rupture distance (⁠Rrup⁠), time‐averaged shear‐wave velocity in the upper 30 m (⁠VS30⁠), and depth to the top of the rupture plane (⁠Ztor⁠), as well as tectonic and region as input parameters, and predicts various median orientation‐independent horizontal component ground‐motion intensity measures such as peak ground displacement, peak ground velocity, peak ground acceleration, and 5%‐damped pseudospectral acceleration values at spectral periods of 0.01–10 s in log scale. Although no functional form is defined, the response spectra and the distance and magnitude scaling trends of the weighted average ensemble model are consistent and comparable with the NGA‐Sub GMMs, with slightly lower standard deviations. A mixed effects regression analysis is used to partition the total aleatory variability into between‐event, between‐station, and event‐site‐corrected components. The derived global GMMs are applicable to interface earthquakes with M 4.9–9.12, 14≤Rrup≤1000 km⁠, and Ztor≤47 km for sites having VS30values between 95 and 2230 m/s. For intraslab events, the derived global GMMs are applicable to M 4.0–8.0, 28≤Rrup≤1000 km⁠, and 30≤Ztor≤200 km for sites having VS30 values between 95 and 2100 m/s.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"123 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140803334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Summary of the Discussions During the 2023 SSA Topical Meeting on “Future Directions for Physics‐Based Ground Motion Modeling”","authors":"Hiroshi Kawase, Annemarie Baltay","doi":"10.1785/0220240084","DOIUrl":"https://doi.org/10.1785/0220240084","url":null,"abstract":"The Seismological Society of America (SSA) topical conference, Future Directions for Physics‐Based Ground Motion Modeling, was held in Vancouver, Canada, on 10–13 October 2023, co‐sponsored by the Seismological Society of Japan and co‐chaired by Annemarie Baltay of the U.S. Geological Survey and Hiroshi Kawase of Kyoto University. This meeting brought together many researchers and practitioners interested in modeling, observing, and utilizing ground‐motion models (GMMs). Scientists gathered to discuss complex kinematic and dynamic rupture simulation approaches, empirical representations of the earthquake source, site and path effects, physical modeling of the recording site, challenges for model extrapolation, and overall prediction accuracy and...","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"23 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140803337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SSA 2024 Annual Meeting","authors":"","doi":"10.1785/0220240136","DOIUrl":"https://doi.org/10.1785/0220240136","url":null,"abstract":"Abstract not available","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"12 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140628005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"2023 Eastern Section SSA Annual Meeting Report 22–24 October 2023","authors":"","doi":"10.1785/0220230428","DOIUrl":"https://doi.org/10.1785/0220230428","url":null,"abstract":"The 95th Annual Meeting of the Eastern Section of the Seismological Society of America (ES‐SSA) was held on 22–24 October 2023. The meeting was held in person at Southern Methodist University (SMU) in Dallas, Texas. Just over 80 people registered for the meeting and attended oral sessions over two days (Fig. 1). We held six oral sessions with 35 presentations and had two blocks of time to view and discuss 28 posters, which remained on display during the entire meeting.On Sunday, 22 October 2023, a field trip to explore the Wichita Mountains and the Meers Fault in Oklahoma....","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"6 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139924298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}