Journal of Seismology最新文献

{"title":"Nowcasting earthquakes in the Philippines archipelago","authors":"Sonu Devi,&nbsp;Sumanta Pasari","doi":"10.1007/s10950-024-10277-6","DOIUrl":"10.1007/s10950-024-10277-6","url":null,"abstract":"<div><p>The continuous occurrence of destructive earthquakes in the Philippine Archipelago, generated by both mapped and unmapped faults, highlights the shortcomings of traditional fault-based hazard assessment techniques. The earthquakes caused by unmapped faults, in particular, emphasize the necessity of adopting area-based hazard evaluation approaches. In view of this, the present study implements an area–based earthquake nowcasting approach to statistically compute the current level of seismic hazards in 26 densely populated cities across Philippines. We utilize the concept of natural time, the inter–event counts of small earthquakes occurring between successive large earthquakes, to calculate Earthquake Potential Score (EPS) for the defined city regions. To derive the natural time statistics, we incorporate a diverse range of reference probability distributions, including heavy–tailed, time–dependent, time–independent, and exponentiated group of distributions. Statistical inference for observed natural times reveals that (1) the Weibull distribution provides the best representation; (2) as on August 15, 2024, the EPS values (%), corresponding to M <span>(ge )</span> 6.5 earthquakes for 26 cities range from 09% to 71%, with Tacloban (71%), Cagayan de Oro (69%), Dasmarinas (64%), Bacoor (63%), Las Pinas (63%), Manila (62%), Paranaque (61%), Taguig (60%), Valenzuela (60%), Makati (60%), Quezon City (58%), Pasig (58%), Caloocan (56%), Antipolo (55%), Marawi (55%), Zamboanga (54%), San Jose Del Monte (53%), Legazpi (44%), Cebu (39%), San Carlos (31%), Bacolod (28%), General Santos (27%), and Davao (09%), and (3) the nowcast scores are consistent despite some variations in threshold magnitude and city regions. These EPS values provide a unique measure to determine the ongoing progression of the earthquake cycle of large sized events of the target regions, enabling a consistent city ranking based on their current level of seismic progression. The nowcasting approach and emanated results offer valuable insights for informed decision–making to enhance preparedness and risk management strategies across the Philippine Archipelago.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 2","pages":"505 - 524"},"PeriodicalIF":1.6,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 relationships between macroseismic intensity and local magnitude for the volcanic region of Mt. Etna (Italy)","authors":"Salvatore D’Amico,&nbsp;Tiziana Tuvè,&nbsp;Ambra Mantovani","doi":"10.1007/s10950-024-10274-9","DOIUrl":"10.1007/s10950-024-10274-9","url":null,"abstract":"<div><p>The volcanic region of Mt. Etna (Italy) has a well-documented historical seismic activity, with records of seismic and volcanic events on the volcano dating back to late 1633. This historical data, covering a time span longer than that recorded by instrumental seismological data, is a testament to the reliability of the intensity-magnitude relations, the only means to obtain macroseismic information, the sole indicator of the energy released by earthquakes. Previous studies in the literature have proposed various methods for converting epicentral intensity into macroseismic magnitude for the Etna region. Still, these methods were based on older datasets with limited instrumental data. The updated relationship proposed in the paper significantly improves the accuracy of macroseismic magnitude estimates, aligning them more closely with local magnitudes calculated for recent earthquakes. The study uses a dataset of 58 volcano-tectonic events from 1997 to 2018, with magnitudes between 2.5 and 4.8 and intensities ranging from IV to VIII on the EMS scale. The instrumental magnitudes were obtained from the Mt. Etna seismic catalogue and the Italian seismological database, while macroseismic data were sourced from the macroseismic catalogue of Etnean earthquakes. In the volcanic area of ​​Etna, macroseismic epicenters are often located very close to the sites where the maximum intensity is observed, this is due to the strong attenuation of seismic energy and the shallowness of the epicenters. For this reason, the epicentral intensity is generally assumed to be equal to the maximum intensity. The new relationship is tailored explicitly for shallow earthquakes (H ≤ 3 km), which are the most recurrent. It includes a correction factor for depth, making it applicable to deeper events and enhancing its relevance in real-world scenarios.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 2","pages":"305 - 315"},"PeriodicalIF":1.6,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-024-10274-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modified path-dependent duration in Zagros, for use in stochastic simulation method","authors":"Reza Davoudian,&nbsp;Hamid Zafarani,&nbsp;Ahmad Sadidkhouy","doi":"10.1007/s10950-025-10281-4","DOIUrl":"10.1007/s10950-025-10281-4","url":null,"abstract":"<div><p>The ground-motion duration, the time window in which the ground motion time history is considered to be strong, may be classified into three main groups, i.e., uniform, bracketed, and significant duration. In the current study, the three definitions were employed to argue why \"significant duration\" is the preferred model to calculate shear wave duration and how it was derived using a modified approach. Using the modified approach, for the first time, the path-dependent part was estimated in Zagros region. The Simulated Annealing inversion method was employed to regress a piecewise-linear function to the medians of path duration versus rupture distance. The data used includes acceleration waveforms obtained from the Iranian strong motion network operated by the Building and Housing Research Center of Iran (BHRC). The events occurred between May 1997 and July 2022 with magnitudes between <span>({text{M}}_{text{W}})</span> 5.0 and <span>({text{M}}_{text{W}})</span> 7.3. Using the modified model shows a reduction in duration in the distance range between 100 and 160 km and its effect on ground motion intensity measures (GMIMs). Moreover, the region-specific model predicts a longer duration than those provided by both the traditional model and the model proposed for western North America. Additionally, the contribution of source- and path-dependent duration to the total duration across a wide range of magnitudes and distances was analyzed. The analysis indicated that an accurate estimation of path-dependent duration, even for short distances and large magnitudes, is essential. To demonstrate the reasonableness of the modified model, the EXSIM program (enabling dynamic frequency mode) was employed to simulate peak ground acceleration (PGA) values for earthquakes greater than <span>({text{M}}_{text{W}})</span> 6.0. Additionally, residual analysis illustrated that the modified model predicted PGA with accuracy and negligible trends. We propose that for other regions with different crustal thicknesses, a new region-specific model must be developed.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 2","pages":"439 - 456"},"PeriodicalIF":1.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143930029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rupture zones of the 1978 (Mw 7.6) and 2020 (Mw 7.4) earthquakes in the Oaxaca subduction zone: Implications for seismic slip and seismic hazard","authors":"M. Rosario Martínez-López,&nbsp;Gerardo Suárez,&nbsp;Carlos Mendoza","doi":"10.1007/s10950-024-10275-8","DOIUrl":"10.1007/s10950-024-10275-8","url":null,"abstract":"<div><p>The slip models of the Oaxaca, Mexico earthquakes of 29 November 1978 (<i>M</i>_<i>w</i> 7.6) and 23 June 2020 (M_w 7.4) were estimated by inverting <i>P</i> and <i>SH</i> teleseismic velocity waveforms. The inversion of the 1978 event used broadband and long-period data. In the case of the 2020 event, broadband data were available. In both cases, the rupture zones lie down dip of the hypocenter. It has been suggested that the events of 1978 and 2020 are quasi-repeater earthquakes breaking similar asperities of previous events. Based on this, the slip of the seismic rupture obtained in recent events is used to characterize the slip of previous events, and to calculate the slip deficiency in the four rupture zones defined by the 1928 events. The largest slip deficiency is where the large 7.6 event occurred in October 1928, between the ruptures of 1978 and the <i>Mw</i> 7.2 earthquake of June 2018. Here, no great earthquakes have occurred in the last 96 years, suggesting high accumulation of elastic strain that may generate potentially an earthquake <i>Mw</i> 7.8. This gap separates two regions with different seismic behavior, suggesting a complex rupture process in the Oaxaca subduction zone. The other three regions, where the 1978, 2018, and 2020 earthquakes took place, show average slip deficiencies of 500 cm. The great earthquake of 1787 broke the four rupture areas defined by the 1928 events in a single <i>Mw</i> 8.6 earthquake, consistent with a variable rupture mode that has been observed in other subduction zones of the world. In conclusion, the Oaxaca subduction zone suggests a high seismic potential.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 2","pages":"317 - 336"},"PeriodicalIF":1.6,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-024-10275-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved earthquake locations through a new 1-D P-wave velocity model for the Isthmus of Panama using particle swarm optimization method","authors":"Isaac Guerra Araúz,&nbsp;Katsuichiro Goda","doi":"10.1007/s10950-025-10279-y","DOIUrl":"10.1007/s10950-025-10279-y","url":null,"abstract":"<div><p>The Isthmus of Panama experiences high seismic activity, having the potential for destructive earthquakes and serious risks to the population. Here, we present a new 1-D P-wave velocity model for Panama, which could be used for routine and accurate determination of earthquake locations, since Panama currently relies on a global velocity model. We used 23,178 P-wave arrival times from 1,672 selected seismic events between 2013 and 2022, recorded by 128 seismic stations across the country. To perform the analysis of P-wave arrival times, we utilized the Particle Swarm Optimization (PSO) method, which propagates multiple particles that explore the solution space to find the best possible velocity model. The new 1-D P-wave velocity model was obtained after multiple PSO runs, using the results of the previous run as a starting model until we find a model that best fits the seismic data. This model consists of 10 layers extending to a depth of 70 km, where the velocities range from 5.76 km/s at depths of 0-5 km to 8.27 km/s in the deepest layer. The station corrections, consistent with the geology of the Isthmus, allowed accurate relocation of earthquakes, achieving an epicentral distance error of ±3 km and a hypocentral distance error of ±6 km. These results are not only relevant for 3-D seismic tomography, but also valuable for seismic hazard and risk assessments in the Isthmus of Panama.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 2","pages":"367 - 384"},"PeriodicalIF":1.6,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Earthquakes and seismic hazard for Norway and Svalbard","authors":"Conrad Lindholm,&nbsp;Hilmar Bungum,&nbsp;Federica Ghione,&nbsp;Abdelghani Meslem,&nbsp;Chen Huang,&nbsp;Volker Oye","doi":"10.1007/s10950-024-10270-z","DOIUrl":"10.1007/s10950-024-10270-z","url":null,"abstract":"<div><p>We document a complete seismic hazard study for mainland Norway and the Svalbard archipelago. The study is based on a Probabilistic Seismic Hazard Analysis (PSHA) method, and for the first time a new earthquake catalogue is presented publicly that covers Norway, Svalbard and the adjacent offshore regions. The catalogue is developed from an extensive analysis of historical earthquakes combined with more recent instrumental data with 33,864 reports between 1497 through 2018, and with magnitudes up to Mw 6.7. With this catalogue seismic hazard is computed for 10% exceedance in 475 years through a logic tree computation with 12 branches: two area-zonations, one zonation free branch and four GMPEs. These 12 branches were defined with the aim to reduce the model bias, i.e., to centre the model, and to capture the epistemic uncertainty of the results. While the conventional Vs30 reference velocity is usually around 800 m/s we have targeted a reference velocity of 1200 m/s, based on extensive documentation of Norwegian rock velocities. This has significant bearing on the calculated hazard and provides for results that better reflect the bedrock conditions in Norway. As a result of this, the predicted shaking intensities are lower than the values previously reported in the (1998) national building code. In the Supplementary Information we have provided a brief overview of the seismotectonic setting, some tests that further demonstrate the uncertainty in our hazard estimates, a model for H/V ground-motion response spectra, examples of the sensitivity to the bedrock reference velocity and a comparison between the present study and the ESHM20 results.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 1","pages":"107 - 126"},"PeriodicalIF":1.6,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-024-10270-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of PGV and response spectra on human walking states in simulated earthquake scenarios","authors":"Li Tiefei,&nbsp;Chi Mingjie,&nbsp;Chen Xueliang,&nbsp;Liu Xinyu,&nbsp;Li Zongchao,&nbsp;Ji Zhiwei,&nbsp;Chu Jian","doi":"10.1007/s10950-024-10276-7","DOIUrl":"10.1007/s10950-024-10276-7","url":null,"abstract":"<div><p>Scenario-based disaster prevention, preparedness, and response are developing trends in contingency management. Human walking states in simulated scenarios are studied in this work on the Intelligent Seismic Scenario Experience vibration table. The vibration table adopts a comprehensive method that considers the seismic characteristics, building structure, and dynamic performance of the equipment to ensure the real experience of the human body in earthquake scenarios. The equipment can conduct a full chain of earthquake scenario simulation: based on source physical processes, seismic wave propagation paths, site conditions, and building structures. Seismic scenarios of different sources, site conditions, floors, and response spectra are used to study human perception and reactions during walking. The experimental results are consistent with the description of human action at the current intensity scales of China, Europe, the USA, and Japan. Research shows that the PGV has a significant correlation with the impact of ground motion on human walking and can be used as a key indicator to determine the intensity. However, the correlation between the PGA and the impact on human walking is not strong. The predominant period of the response spectrum is also a key factor affecting human walking states in earthquake scenarios. Vibrations with periods between 0.5 s and 1.9 s have the greatest impact on the walking state, which is usually caused by high-rise buildings and deep soil sites and needs special attention. Moreover, horizontal vibrations dominate impacts on human walking in earthquake scenarios where the PGA ≤ 300 Gal. The results of this experiment can be applied to the study of the relationships between the macroscopic intensity and instrument intensity, the preparation of earthquake intensity scales, guidance on earthquake emergency avoidance actions, and the popularization of earthquake science.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 1","pages":"171 - 185"},"PeriodicalIF":1.6,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The prediction equation for the significant duration of strong motion in the Sichuan-Yunnan region of China","authors":"Ping Liu,&nbsp;Qingsong Yang,&nbsp;Tao Ma,&nbsp;Tiantian Hui,&nbsp;Jinyue Zhang","doi":"10.1007/s10950-024-10273-w","DOIUrl":"10.1007/s10950-024-10273-w","url":null,"abstract":"<div><p>The significant duration is a crucial intensity measure for earthquake-resistant design and seismic hazard assessment (SHA). The Sichuan-Yunnan region is characterized by a high level of seismic activity and possesses the most concentrated network of seismic stations in China. The ground motion prediction equation (GMPE) is the predominant approach to estimating significant durations. The existing prediction equations for the significant duration are not well-suited for the Sichuan-Yunnan region. This study used data from the National Strong Motion Observation Network System (NSMONS) of China in this region to develop prediction equations for significant durations of <i>D</i>_S5-75 and <i>D</i>_S5-95. The equations took into account variables including moment magnitude (<i>M</i>_w), fault distance (<i>R</i>_rup), average shear wave velocity of 30 m on the soil profile (<i>V</i>_S30), and depth to the top of the rupture (<i>Z</i>_tor). Our database has a singular instance of the Wenchuan earthquake with <i>M</i>_w &gt; 7. The restricted data complicates the calibration of our model for events with <i>M</i>_w &gt; 7. Therefore, we suggest the equations be valid in the Sichuan-Yunnan region for <i>M</i>_w between 4.2 and 7.0, <i>R</i>_rup from 0 to 300 km, and <i>V</i>_S30 values ranging from 139 to 900 m/s.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 1","pages":"199 - 219"},"PeriodicalIF":1.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence of soil amplification and damage in Centro, Tabasco, southern México due to distant large earthquakes","authors":"Carmen Maricela Gómez-Arredondo,&nbsp;Juan Carlos Montalvo-Arrieta,&nbsp;Adalberto Rodríguez-Vázquez,&nbsp;Daniel Andrés Damas-López,&nbsp;Guillermo Chávez-Hernández","doi":"10.1007/s10950-024-10272-x","DOIUrl":"10.1007/s10950-024-10272-x","url":null,"abstract":"<div><p>There are only a few worldwide cases where distant earthquakes have caused damage. One such example is the municipality of Centro located in Tabasco, Southeast Mexico, approximately 360 km from the Mesoamerican trench, where a strong ground shaking was felt during the <i>M</i>_w8.2 earthquake of September 08, 2017. In this study, for 20 sites shear-wave velocity profiles were determined using Multichannel Analysis of Surface Wave and <i>V</i>_P profiles using Seismic Refraction techniques. Also <i>V</i>_<i>S30</i> (shear-wave velocity up to a depth of 30 m) values were obtained for the same sites. The distribution of the <i>V</i>_<i>S30</i> values in the study area varied from 120 m/s to 570 m/s and it was observed that sites where damage to buildings were reported lie near areas with <i>V</i>_<i>S30</i> &lt; 270 m/s. Additionally, the transfer functions of the 20 sites were estimated using the Thomson-Haskell method. The fundamental frequencies (<i>f</i>₀) obtained through transfer functions had values varying from 0.9 ≤ <i>f</i>_<i>0</i> ≤ 2.0 Hz. These transfer functions were convolved with the signal that represents the record in the bottom of the soil column in the study area to obtain synthetic accelerograms in the municipality of Centro. The only accelerograph station located in the study area (VHSA station) was used as a reference site. The horizontal-to-vertical spectral ratio of the VHSA location was used for site characterization to assess the effects of regional events. The study concludes that several factors contribute to the susceptibility of Centro municipality to distant seismic events. These factors include low shear-wave velocity (<i>V</i>_<i>s</i>), low fundamental frequency (<i>f</i>_<i>0</i>), local site conditions, the presence of buildings on former lake zones, low seismic wave attenuation, and the regions’ overall vulnerability to regional earthquakes.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 1","pages":"65 - 84"},"PeriodicalIF":1.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating site amplifications of the longmenshan region through inversions of the aftershock data","authors":"Yuzhu Bai","doi":"10.1007/s10950-024-10271-y","DOIUrl":"10.1007/s10950-024-10271-y","url":null,"abstract":"<div><p>Considering 1173 recordings of 35 stations from 67 aftershocks of the 12 May 2008 Wenchuan <i>M</i>_w (moment magnitude) 7.9 earthquake, we investigate site amplifications and their variations in the Longmenshan region. Site responses of 35 stations are analyzed using the coda-wave and S-wave methods. For these methods, the site amplifications are computed using a generalized inversion method. Generally, the calculated site amplifications from coda-wave and S-wave inversions are not very large, which is probably resulted from the special geology conditions in the Longmenshan region and most peak ground acceleration values of recordings less than 0.1 g. Because coda-wave amplitudes attenuate slowly along the propagation path, the site amplifications computed through the coda-wave inversion are relatively larger than those through the S-wave inversion. The comparison of the intraevent and interevent residuals of the coda-wave inversion with those of S-wave inversion demonstrates that the coda-wave inversion is more reasonable to calculate the site amplifications of the Longmenshan region. Moreover, for the Longmenshan region, the averaged site amplifications of the young geology sediments are not considerably different from those of the old geology rocks in some frequencies. If the sites of stations are classified by the National Earthquake Hazard Risk Reduction Program (NEHRP) site classifications, the averaged site coefficients of the Longmenshan region are usually smaller than the corresponding NEHRP site coefficients.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 1","pages":"47 - 64"},"PeriodicalIF":1.6,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}