Abstract The 1920 Ms 8.5 Haiyuan earthquake was the largest rupture in China in the twentieth century; however, the coseismic slip characteristics that provide insight into fault kinematics and future seismic hazards are unknown. In this study, we employed stochastic slip modeling to explore plausible slip distributions for this earthquake, incorporating different geodetic fault coupling models as prior constraints. Results demonstrate that fault coupling constraints have both positive and negative effects on stochastic models generating slip scenarios to fit the field-measured geomorphic offset observations. Notably, a Gauss coupling model helps to generate surface slip with higher probabilities to fit geomorphic offsets, exhibiting a closer resemblance to the slip distribution of the Haiyuan earthquake. Integrating 41 slip scenarios of 6000 that reasonably fit the geomorphic offsets, we find that the Haiyuan earthquake likely involved multiple asperities and occurred as a cascading rupture event. The western and eastern fault segments may involve shallow slip deficits, implying potential distributed and/or off-fault deformation during the earthquake, with implications for geomorphic offset–based interpretations of long-term fault behavior. The modeling not only provides insight into the kinematics of the Haiyuan earthquake but also offers a plausible scheme for investigating historical earthquakes.
{"title":"Interseismic Coupling–Based Stochastic Slip Modeling of the 1920 Ms 8.5 Haiyuan Earthquake","authors":"Yanchuan Li, Xinjian Shan, Zhiyu Gao, Chunyan Qu","doi":"10.1785/0220230253","DOIUrl":"https://doi.org/10.1785/0220230253","url":null,"abstract":"Abstract The 1920 Ms 8.5 Haiyuan earthquake was the largest rupture in China in the twentieth century; however, the coseismic slip characteristics that provide insight into fault kinematics and future seismic hazards are unknown. In this study, we employed stochastic slip modeling to explore plausible slip distributions for this earthquake, incorporating different geodetic fault coupling models as prior constraints. Results demonstrate that fault coupling constraints have both positive and negative effects on stochastic models generating slip scenarios to fit the field-measured geomorphic offset observations. Notably, a Gauss coupling model helps to generate surface slip with higher probabilities to fit geomorphic offsets, exhibiting a closer resemblance to the slip distribution of the Haiyuan earthquake. Integrating 41 slip scenarios of 6000 that reasonably fit the geomorphic offsets, we find that the Haiyuan earthquake likely involved multiple asperities and occurred as a cascading rupture event. The western and eastern fault segments may involve shallow slip deficits, implying potential distributed and/or off-fault deformation during the earthquake, with implications for geomorphic offset–based interpretations of long-term fault behavior. The modeling not only provides insight into the kinematics of the Haiyuan earthquake but also offers a plausible scheme for investigating historical earthquakes.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":" 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135242642","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}
Yuyang Tan, Ning Gu, Huilin Xing, Yong Zhang, Zongwei Jin, Sibo Hua, Jianchao Wang, Mutian Qin, Shuo Pang, Sanzhong Li
Abstract We determined the rupture model of the 2021 Mw 7.1 Fukushima earthquake near northeastern Japan in this study and adopted this model to investigate the cause of this earthquake and its aftershocks. The rupture model was obtained through joint inversion of teleseismic, strong-motion and geodetic data. It is shown that the slips were predominantly distributed on the southwest side of the earthquake epicenter, indicating a unilateral rupture event. We observed that the seismic moment was released in three time periods, producing four slip patches on the fault plane. Through comparison, we demonstrated that our joint inversion model was more reliable in describing the rupture process of the Fukushima earthquake than the automatic inversion models determined using only strong-motion data. By jointly analyzing the slip distribution and seismic velocity structure, we found a good correlation between the slip patches and VP/VS anomalies, suggesting that structural heterogeneities along the fault zone played a critical role in controlling the rupture process of the Fukushima earthquake. In addition, most aftershocks were located in the region characterized by small slips and high VP/VS, and we demonstrated that they were caused by stress changes due to the presence of fluids and the rupture of the mainshock.
{"title":"Structural Heterogeneity Controlled Rupture Process of the 2021 Mw 7.1 Fukushima, Japan, Earthquake Revealed by Joint Inversion of Seismic and Geodetic Data","authors":"Yuyang Tan, Ning Gu, Huilin Xing, Yong Zhang, Zongwei Jin, Sibo Hua, Jianchao Wang, Mutian Qin, Shuo Pang, Sanzhong Li","doi":"10.1785/0220230259","DOIUrl":"https://doi.org/10.1785/0220230259","url":null,"abstract":"Abstract We determined the rupture model of the 2021 Mw 7.1 Fukushima earthquake near northeastern Japan in this study and adopted this model to investigate the cause of this earthquake and its aftershocks. The rupture model was obtained through joint inversion of teleseismic, strong-motion and geodetic data. It is shown that the slips were predominantly distributed on the southwest side of the earthquake epicenter, indicating a unilateral rupture event. We observed that the seismic moment was released in three time periods, producing four slip patches on the fault plane. Through comparison, we demonstrated that our joint inversion model was more reliable in describing the rupture process of the Fukushima earthquake than the automatic inversion models determined using only strong-motion data. By jointly analyzing the slip distribution and seismic velocity structure, we found a good correlation between the slip patches and VP/VS anomalies, suggesting that structural heterogeneities along the fault zone played a critical role in controlling the rupture process of the Fukushima earthquake. In addition, most aftershocks were located in the region characterized by small slips and high VP/VS, and we demonstrated that they were caused by stress changes due to the presence of fluids and the rupture of the mainshock.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":" 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135242646","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}
Nanang T. Puspito, Bambang S. Prayitno, Andri D. Nugraha, David P. Sahara, Dian Kusumawati, Zulfakriza Zulfakriza, Shindy Rosalia, Daryono Daryono, Nova Heryandoko, Ajat Sudrajat, Pepen Supendi, Suko P. Adi, Dwikorita Karnawati
Abstract Indonesia’s tectonic setting has resulted in a high level of seismic activity, which makes seismic networks and early warning systems vital for this country. Indonesia’s seismic stations, a total of 411 stations in 2021, are maintained by the Meteorological, Climatological, and Geophysical Agency (BMKG). This study attempts to evaluate station performance, because these are crucial in monitoring seismic activity. We utilized information from the BMKG 2020 and 2019 seismic catalogs to analyze the performance of the stations. A total of 13,798 events were reported in 2019 with magnitudes (MLv) of up to 8, whereas 10,163 events with similar magnitudes were reported in 2020. Stations in the eastern part of Indonesia (Sulawesi, Lesser Sunda Islands, the Moluccas, and Papua) detected more events compared to stations in the western part of Indonesia (Borneo, Sumatra, and Java). Up to 1651 events were detected by a single station in eastern Indonesia, compared to 847 events in western Indonesia. BMKG stations in eastern Indonesia have recorded ample amounts of events, which is consistent with the high seismic activity found there. In terms of station coverage, events in the eastern part have better station coverage due to smaller azimuthal gaps, considering the geographic location. We also analyzed station performance and the number of recorded stations in terms of a function of time for each event in the Sumatra, Sulawesi, Lesser Sunda Islands, and Papua regions. Although the number of recordings obtained by stations was high after 15 s since the origin time, the azimuthal gap progression in Sumatra and Java remained large. Therefore, an additional ocean-bottom seismometer needs to be installed in the Sumatra–Java trench.
{"title":"Evaluation of Station Performance of the Indonesian Seismic Network Using the Primary Location Parameter","authors":"Nanang T. Puspito, Bambang S. Prayitno, Andri D. Nugraha, David P. Sahara, Dian Kusumawati, Zulfakriza Zulfakriza, Shindy Rosalia, Daryono Daryono, Nova Heryandoko, Ajat Sudrajat, Pepen Supendi, Suko P. Adi, Dwikorita Karnawati","doi":"10.1785/0220220334","DOIUrl":"https://doi.org/10.1785/0220220334","url":null,"abstract":"Abstract Indonesia’s tectonic setting has resulted in a high level of seismic activity, which makes seismic networks and early warning systems vital for this country. Indonesia’s seismic stations, a total of 411 stations in 2021, are maintained by the Meteorological, Climatological, and Geophysical Agency (BMKG). This study attempts to evaluate station performance, because these are crucial in monitoring seismic activity. We utilized information from the BMKG 2020 and 2019 seismic catalogs to analyze the performance of the stations. A total of 13,798 events were reported in 2019 with magnitudes (MLv) of up to 8, whereas 10,163 events with similar magnitudes were reported in 2020. Stations in the eastern part of Indonesia (Sulawesi, Lesser Sunda Islands, the Moluccas, and Papua) detected more events compared to stations in the western part of Indonesia (Borneo, Sumatra, and Java). Up to 1651 events were detected by a single station in eastern Indonesia, compared to 847 events in western Indonesia. BMKG stations in eastern Indonesia have recorded ample amounts of events, which is consistent with the high seismic activity found there. In terms of station coverage, events in the eastern part have better station coverage due to smaller azimuthal gaps, considering the geographic location. We also analyzed station performance and the number of recorded stations in terms of a function of time for each event in the Sumatra, Sulawesi, Lesser Sunda Islands, and Papua regions. Although the number of recordings obtained by stations was high after 15 s since the origin time, the azimuthal gap progression in Sumatra and Java remained large. Therefore, an additional ocean-bottom seismometer needs to be installed in the Sumatra–Java trench.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"5 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135480528","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}
Romano Camassi, Viviana Castelli, Enrico Serpelloni, Silvia Pondrelli
Abstract The 1695 Mw 6.4 Asolano earthquake is the southernmost of the six largest earthquakes to have occurred in northeast Italy or nearby (the others being 1348 Mw 6.6 Eastern Alps; 1511 Mw 6.3 Friuli-Slovenia; 1873 Mw 6.2 Alpago-Cansiglio; 1936 Mw 6.1 Alpago-Cansiglio; 1976 Mw 6.4 Friuli). The 1695 earthquake is generally associated with the Montello thrust, with most recent studies locating it on the eastern slope of Montello Hill. A full-scale reappraisal of all available historical data leads this study to a more robust macroseismic localization of the 1695 earthquake and to open toward other possible locations of the seismic source that produced it. In particular, it becomes feasible to place its epicenter at the foothills of the Monte Grappa massif, the major morphological expression of the Bassano–Valdobbiadene thrust fault. Here, we describe the reasons that make this fault a possible alternative to previous hypotheses.
{"title":"Reappraising the 25 February 1695 Asolano Earthquake","authors":"Romano Camassi, Viviana Castelli, Enrico Serpelloni, Silvia Pondrelli","doi":"10.1785/0220230238","DOIUrl":"https://doi.org/10.1785/0220230238","url":null,"abstract":"Abstract The 1695 Mw 6.4 Asolano earthquake is the southernmost of the six largest earthquakes to have occurred in northeast Italy or nearby (the others being 1348 Mw 6.6 Eastern Alps; 1511 Mw 6.3 Friuli-Slovenia; 1873 Mw 6.2 Alpago-Cansiglio; 1936 Mw 6.1 Alpago-Cansiglio; 1976 Mw 6.4 Friuli). The 1695 earthquake is generally associated with the Montello thrust, with most recent studies locating it on the eastern slope of Montello Hill. A full-scale reappraisal of all available historical data leads this study to a more robust macroseismic localization of the 1695 earthquake and to open toward other possible locations of the seismic source that produced it. In particular, it becomes feasible to place its epicenter at the foothills of the Monte Grappa massif, the major morphological expression of the Bassano–Valdobbiadene thrust fault. Here, we describe the reasons that make this fault a possible alternative to previous hypotheses.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135819592","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}
Abstract The site-specific amplification of seismic waves is an essential component of local seismic hazard assessment. It can be evaluated from empirical data, but measurements are feasible just in a limited number of locations. Hence, at the city scale, there is a need for the theoretical prediction and interpolation of the amplification. In this article, we introduce a physics-based method to predict the site-specific amplification and duration in a broad frequency range. The method is based on a novel energy-based concept of the multipath propagation of waves in viscoelastic media with random heterogeneities. The amplification is expressed by the surface-outcrop transfer function of the multipath wave propagation, which is defined by expected values of the energy spectral ratio. The method is applied to the near-surface 2D velocity model in the city of Zürich in Switzerland. The predicted amplification is validated by empirical data at a nearby seismic station, and it is compared with the soil class and other site-condition proxies. Finally, the method performance is demonstrated by the prediction of site-specific seismic waveforms and response spectra for the 2022 ML 4.7 Mulhouse earthquake.
{"title":"Multipath Transfer-Function Correction Method to Predict Site-Specific Amplification at City Scale","authors":"Miroslav Hallo, Paolo Bergamo, Donat Fäh","doi":"10.1785/0220230213","DOIUrl":"https://doi.org/10.1785/0220230213","url":null,"abstract":"Abstract The site-specific amplification of seismic waves is an essential component of local seismic hazard assessment. It can be evaluated from empirical data, but measurements are feasible just in a limited number of locations. Hence, at the city scale, there is a need for the theoretical prediction and interpolation of the amplification. In this article, we introduce a physics-based method to predict the site-specific amplification and duration in a broad frequency range. The method is based on a novel energy-based concept of the multipath propagation of waves in viscoelastic media with random heterogeneities. The amplification is expressed by the surface-outcrop transfer function of the multipath wave propagation, which is defined by expected values of the energy spectral ratio. The method is applied to the near-surface 2D velocity model in the city of Zürich in Switzerland. The predicted amplification is validated by empirical data at a nearby seismic station, and it is compared with the soil class and other site-condition proxies. Finally, the method performance is demonstrated by the prediction of site-specific seismic waveforms and response spectra for the 2022 ML 4.7 Mulhouse earthquake.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"64 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135868482","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}
Zhangbao Cheng, Yen Joe Tan, Fan Zhang, Pengcheng Zhou, Jian Lin, Jinyu Tian, Xubo Zhang, Caicai Zha
Abstract Earthquake monitoring and many seismological studies depend on seismic phase arrivals. Thus, detecting seismic events and picking the phase arrival times are fundamentally important. In the recent years, seismic phase picking models based on deep learning approaches have been widely developed. These deep learning models can achieve better performances than traditional phase picking methods and improve the quality of phase picking for land-based earthquake monitoring. However, these models might not perform well on data from ocean-bottom seismometers (OBSs), because they are trained exclusively using onshore seismic data and have limited out-of-distribution generalization ability. Nevertheless, there are insufficient labeled OBS phase arrivals dataset to train a deep learning model from scratch. In this study, we developed an automatic phase detection model for OBS data (OBS phase detection [OBSPD]) using the transfer learning approach based on an existing U-GPD model with pretrained weights from a generalized phase detection model feature extraction system. We developed OBSPD with a limited amount of training data (2784 three-component event waveforms) from the Cascadia subduction zone (CSZ) OBS deployments. Our results show that transfer learning can achieve lower model loss with less overfitting compared to when training a model from scratch. Our new OBSPD model outperforms four existing deep learning pickers in terms of phase detection accuracy with smaller arrival time residuals on a test OBS dataset at CSZ, especially for P phases.
{"title":"An Efficient Transfer Learning-Based OBS Seismic Phase Picker (OBSPD) Trained on Cascadia Subduction Zone Earthquake Dataset","authors":"Zhangbao Cheng, Yen Joe Tan, Fan Zhang, Pengcheng Zhou, Jian Lin, Jinyu Tian, Xubo Zhang, Caicai Zha","doi":"10.1785/0220230161","DOIUrl":"https://doi.org/10.1785/0220230161","url":null,"abstract":"Abstract Earthquake monitoring and many seismological studies depend on seismic phase arrivals. Thus, detecting seismic events and picking the phase arrival times are fundamentally important. In the recent years, seismic phase picking models based on deep learning approaches have been widely developed. These deep learning models can achieve better performances than traditional phase picking methods and improve the quality of phase picking for land-based earthquake monitoring. However, these models might not perform well on data from ocean-bottom seismometers (OBSs), because they are trained exclusively using onshore seismic data and have limited out-of-distribution generalization ability. Nevertheless, there are insufficient labeled OBS phase arrivals dataset to train a deep learning model from scratch. In this study, we developed an automatic phase detection model for OBS data (OBS phase detection [OBSPD]) using the transfer learning approach based on an existing U-GPD model with pretrained weights from a generalized phase detection model feature extraction system. We developed OBSPD with a limited amount of training data (2784 three-component event waveforms) from the Cascadia subduction zone (CSZ) OBS deployments. Our results show that transfer learning can achieve lower model loss with less overfitting compared to when training a model from scratch. Our new OBSPD model outperforms four existing deep learning pickers in terms of phase detection accuracy with smaller arrival time residuals on a test OBS dataset at CSZ, especially for P phases.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"62 7‐8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135868495","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}
Abstract Although the Italian seismic catalogs are considered among those with the best historical completeness, for periods prior to the Modern era they have gaps, often concentrated in limited regions. For example, Marche, a central Apennine region with high seismicity level, lacks any macroseismic observations throughout the entire fifteenth century. The chance discovery of a destructive earthquake summarized in a note written on a Hebrew prayer manuscript from 1446, not only helps us partially fill a gap in the seismic history of Italy but also prompts us to reflect on how much we still do not know about seismogenesis even in times covered by written sources.
{"title":"All the People of Israel Are Friends: An Unknown Mid-Fifteenth Century Earthquake in the Marche Region (Central Italian Apennines) Recorded in a Coeval Hebrew Manuscript","authors":"Paolo Galli","doi":"10.1785/0220230209","DOIUrl":"https://doi.org/10.1785/0220230209","url":null,"abstract":"Abstract Although the Italian seismic catalogs are considered among those with the best historical completeness, for periods prior to the Modern era they have gaps, often concentrated in limited regions. For example, Marche, a central Apennine region with high seismicity level, lacks any macroseismic observations throughout the entire fifteenth century. The chance discovery of a destructive earthquake summarized in a note written on a Hebrew prayer manuscript from 1446, not only helps us partially fill a gap in the seismic history of Italy but also prompts us to reflect on how much we still do not know about seismogenesis even in times covered by written sources.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"37 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272832","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}
Abstract Cross-correlating continuous seismic data is a commonly employed technique to extract coherent signals to image and monitor the subsurface. However, due largely to site effects and poorly characterized noise sources in oceanic environments, its application to ocean-bottom seismometer (OBS) recordings often requires additional processing. In this contribution, we propose a method to improve the quality of the retrieved surface waves from OBS data and characterize the noise sources. We first cluster the pre-stack noise cross-correlation functions (NCFs) based on a sequencing algorithm, followed by selectively stacking those consisting of coherent and stable signals that are consistent with predicted surface-wave arrival times. Synthetic tests show that the sequenced NCFs can be used to recover the spatial and temporal distribution of noise sources. Applying the method to an OBS array offshore California increases the signal-to-noise ratios of the obtained Rayleigh waves. In addition, we find that the annual temporal distribution of selected NCFs with frequencies ranging from 0.04 to 0.1 Hz is nearly homogeneous during the recording period. In contrast, many NCFs excluded for stacking are temporally clustered. This method has the potential to be applied to other OBS recordings or possibly onland deployments, thus helping to obtain high-quality surface waves and to analyze temporal noise source characteristics.
{"title":"Sequencing Seismic Noise Correlations for Improving Surface Wave Retrieval and Characterizing Noise Sources","authors":"Hongjian Fang","doi":"10.1785/0220230151","DOIUrl":"https://doi.org/10.1785/0220230151","url":null,"abstract":"Abstract Cross-correlating continuous seismic data is a commonly employed technique to extract coherent signals to image and monitor the subsurface. However, due largely to site effects and poorly characterized noise sources in oceanic environments, its application to ocean-bottom seismometer (OBS) recordings often requires additional processing. In this contribution, we propose a method to improve the quality of the retrieved surface waves from OBS data and characterize the noise sources. We first cluster the pre-stack noise cross-correlation functions (NCFs) based on a sequencing algorithm, followed by selectively stacking those consisting of coherent and stable signals that are consistent with predicted surface-wave arrival times. Synthetic tests show that the sequenced NCFs can be used to recover the spatial and temporal distribution of noise sources. Applying the method to an OBS array offshore California increases the signal-to-noise ratios of the obtained Rayleigh waves. In addition, we find that the annual temporal distribution of selected NCFs with frequencies ranging from 0.04 to 0.1 Hz is nearly homogeneous during the recording period. In contrast, many NCFs excluded for stacking are temporally clustered. This method has the potential to be applied to other OBS recordings or possibly onland deployments, thus helping to obtain high-quality surface waves and to analyze temporal noise source characteristics.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272685","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}
Christopher J. DiCaprio, Chris B. Chamberlain, Sanjay S. Bora, Brendon A. Bradley, Matthew C. Gerstenberger, Anne M. Hulsey, Pablo Iturrieta, Marco Pagani, Michele Simionato
Abstract National-scale seismic hazard models with large logic trees can be difficult to calculate using traditional seismic hazard software. To calculate the complete 2022 revision of the New Zealand National Seismic Hazard Model—Te Tauira Matapae Pūmate Rū i Aotearoa, including epistemic uncertainty, we have developed a method in which the calculation is broken into two separate stages. This method takes advantage of logic tree structures that comprise multiple, independent logic trees from which complete realizations are formed by combination. In the first stage, we precalculate the independent realizations of the logic trees. In the second stage, we assemble the full ensemble of logic tree realizations by combining components from the first stage. Once all realizations of the full logic tree have been calculated, we can compute aggregate statistics for the model. This method benefits both from the reduction in the amount of computation necessary and its parallelism. In addition to facilitating the computation of a large seismic hazard model, the method described can also be used for sensitivity testing of model components and to speed up experimentation with logic tree structure and weights.
具有大型逻辑树的国家级地震灾害模型难以用传统的地震灾害软件进行计算。为了计算2022年新西兰国家地震灾害模型(te Tauira Matapae Pūmate ri Aotearoa)的完整修订，包括认知不确定性，我们开发了一种方法，将计算分为两个独立的阶段。这种方法利用了由多个独立逻辑树组成的逻辑树结构，这些逻辑树通过组合形成完整的实现。在第一阶段，我们预先计算逻辑树的独立实现。在第二阶段，我们通过组合第一阶段的组件来组装逻辑树实现的完整集合。一旦计算了完整逻辑树的所有实现，我们就可以计算模型的汇总统计信息。这种方法的好处在于减少了必要的计算量和它的并行性。除了便于大型地震灾害模型的计算外，所描述的方法还可用于模型组件的灵敏度测试，以及加快逻辑树结构和权重的实验速度。
{"title":"Calculation of National Seismic Hazard Models with Large Logic Trees: Application to the NZ NSHM 2022","authors":"Christopher J. DiCaprio, Chris B. Chamberlain, Sanjay S. Bora, Brendon A. Bradley, Matthew C. Gerstenberger, Anne M. Hulsey, Pablo Iturrieta, Marco Pagani, Michele Simionato","doi":"10.1785/0220230226","DOIUrl":"https://doi.org/10.1785/0220230226","url":null,"abstract":"Abstract National-scale seismic hazard models with large logic trees can be difficult to calculate using traditional seismic hazard software. To calculate the complete 2022 revision of the New Zealand National Seismic Hazard Model—Te Tauira Matapae Pūmate Rū i Aotearoa, including epistemic uncertainty, we have developed a method in which the calculation is broken into two separate stages. This method takes advantage of logic tree structures that comprise multiple, independent logic trees from which complete realizations are formed by combination. In the first stage, we precalculate the independent realizations of the logic trees. In the second stage, we assemble the full ensemble of logic tree realizations by combining components from the first stage. Once all realizations of the full logic tree have been calculated, we can compute aggregate statistics for the model. This method benefits both from the reduction in the amount of computation necessary and its parallelism. In addition to facilitating the computation of a large seismic hazard model, the method described can also be used for sensitivity testing of model components and to speed up experimentation with logic tree structure and weights.","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"34 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272691","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":"A Foreign Geophysicist in Marrakesh during Morocco’s Largest Earthquake","authors":"Cristian Farías","doi":"10.1785/0220230334","DOIUrl":"https://doi.org/10.1785/0220230334","url":null,"abstract":"","PeriodicalId":21687,"journal":{"name":"Seismological Research Letters","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135872242","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}
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