Pub Date : 2023-09-25DOI: 10.26443/seismica.v2i2.527
Danielle Sumy
Geocoding is a spatial analysis method that uses address information (e.g., street address, intersection, census tract, zip code, etc.) to determine geographical coordinates (latitude and longitude). In recent decades, geocoding has gone beyond its primary use for census and demographic information to novel applications in disaster risk reduction, even to earthquake early warning. Here I demonstrate the usefulness of geocoding techniques to earthquake early warning systems as applied to case studies that relied on survey response data and crowd-sourced video footage. These datasets were initially collected to understand the efficacy of tests conducted on ShakeAlert®, the earthquake early warning system for the West Coast of the United States, and how people behave during earthquakes, respectively. Geocoding these data can improve our overall technical understanding of the system, demonstrate whether individuals take protective actions such as ‘Drop, Cover, and Hold On’, and spotlight community demographics that the system is reaching or unintentionally missing. The combination of these social science datasets with geocoding information deepens our knowledge of these fundamentally human-centered systems, including how to improve the distribution of alerts for people and individuals with access and functional needs. In the future, this work may help verify U.S. Geological Survey ‘Did You Feel It?’ responses and seismic intensity, especially in regions with sparse seismic networks.
{"title":"Geocoding Applications for Social Science to Improve Earthquake Early Warning","authors":"Danielle Sumy","doi":"10.26443/seismica.v2i2.527","DOIUrl":"https://doi.org/10.26443/seismica.v2i2.527","url":null,"abstract":"Geocoding is a spatial analysis method that uses address information (e.g., street address, intersection, census tract, zip code, etc.) to determine geographical coordinates (latitude and longitude). In recent decades, geocoding has gone beyond its primary use for census and demographic information to novel applications in disaster risk reduction, even to earthquake early warning. Here I demonstrate the usefulness of geocoding techniques to earthquake early warning systems as applied to case studies that relied on survey response data and crowd-sourced video footage. These datasets were initially collected to understand the efficacy of tests conducted on ShakeAlert®, the earthquake early warning system for the West Coast of the United States, and how people behave during earthquakes, respectively. Geocoding these data can improve our overall technical understanding of the system, demonstrate whether individuals take protective actions such as ‘Drop, Cover, and Hold On’, and spotlight community demographics that the system is reaching or unintentionally missing. The combination of these social science datasets with geocoding information deepens our knowledge of these fundamentally human-centered systems, including how to improve the distribution of alerts for people and individuals with access and functional needs. In the future, this work may help verify U.S. Geological Survey ‘Did You Feel It?’ responses and seismic intensity, especially in regions with sparse seismic networks.","PeriodicalId":498743,"journal":{"name":"Seismica","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135769445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-18DOI: 10.26443/seismica.v2i2.389
Brian Kennett, Chengxin Jiang, Krystyna Smolinski
The use of cross-correlation between seismic stations has had widespread applications particularly in the exploitation of ambient seismic noise. We here show how the effects of a non-ideal noise distribution can be understood by looking directly at correlation properties and show how the behaviour can be readily visualised for both seismometer and DAS configurations, taking into account directivity effects. For sources lying in a relatively narrow cone around the extension of the inter-station path, the dispersion properties of the correlation relate directly to the zone between the stations. We illustrate the successful use of correlation analysis for both a large-N array perpendicular to a major highway and DAS cable along a busy road. For correlation work, the co-array consisting of the ensemble of inter-station vectors provides an effective means of assessing the behaviour of array layouts, supplementing the standard plane-wave array response. When combined with knowledge of the suitable correlation zones for noise sources, the co-array concept provides a useful way to design array configurations for both seismometer arrays and DAS.
{"title":"Local station correlation: large N-arrays and DAS","authors":"Brian Kennett, Chengxin Jiang, Krystyna Smolinski","doi":"10.26443/seismica.v2i2.389","DOIUrl":"https://doi.org/10.26443/seismica.v2i2.389","url":null,"abstract":"The use of cross-correlation between seismic stations has had widespread applications particularly in the exploitation of ambient seismic noise. We here show how the effects of a non-ideal noise distribution can be understood by looking directly at correlation properties and show how the behaviour can be readily visualised for both seismometer and DAS configurations, taking into account directivity effects. For sources lying in a relatively narrow cone around the extension of the inter-station path, the dispersion properties of the correlation relate directly to the zone between the stations. We illustrate the successful use of correlation analysis for both a large-N array perpendicular to a major highway and DAS cable along a busy road. For correlation work, the co-array consisting of the ensemble of inter-station vectors provides an effective means of assessing the behaviour of array layouts, supplementing the standard plane-wave array response. When combined with knowledge of the suitable correlation zones for noise sources, the co-array concept provides a useful way to design array configurations for both seismometer arrays and DAS.","PeriodicalId":498743,"journal":{"name":"Seismica","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135153701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-13DOI: 10.26443/seismica.v2i2.384
Alexandre Plourde
Spatiotemporal variations in the magnitude of completeness Mc make it challenging to confidently assess seismic hazard or even to simply compare earthquake rates between regions. In this study, we introduce new techniques to correct for heterogeneous Mc in a treatment of the eastern and Atlantic Canada earthquake catalog (1985--2022). We first introduce new methodology to predict Mc(x,t) based on the distribution of seismometers. Second, we introduce a modified maximum-likelihood estimator (MLE) for b (the b-value) that accounts for spatiotemporal Mc variation, allowing the inclusion of more earthquakes. Third, we compute the ratio of detected/predicted M>1 earthquakes as a function of Mc and apply it to create a calibrated M>1 event-rate map. The resulting map has advantages over a moment-rate map, which is effectively sensitive only to the very largest earthquakes in the dataset. The new MLE results in a modestly more precise b when applied to the Charlevoix Seismic Zone, and a substantial increase in precision when applied to the full Atlantic Canada region. It may prove useful in future hazard assessments, particularly of regions with highly heterogeneous Mc and relatively sparse catalogs.
{"title":"Assessing earthquake rates and b-value given spatiotemporal variation in catalog completeness: Application to Atlantic Canada","authors":"Alexandre Plourde","doi":"10.26443/seismica.v2i2.384","DOIUrl":"https://doi.org/10.26443/seismica.v2i2.384","url":null,"abstract":"Spatiotemporal variations in the magnitude of completeness Mc make it challenging to confidently assess seismic hazard or even to simply compare earthquake rates between regions. In this study, we introduce new techniques to correct for heterogeneous Mc in a treatment of the eastern and Atlantic Canada earthquake catalog (1985--2022). We first introduce new methodology to predict Mc(x,t) based on the distribution of seismometers. Second, we introduce a modified maximum-likelihood estimator (MLE) for b (the b-value) that accounts for spatiotemporal Mc variation, allowing the inclusion of more earthquakes. Third, we compute the ratio of detected/predicted M>1 earthquakes as a function of Mc and apply it to create a calibrated M>1 event-rate map. The resulting map has advantages over a moment-rate map, which is effectively sensitive only to the very largest earthquakes in the dataset. The new MLE results in a modestly more precise b when applied to the Charlevoix Seismic Zone, and a substantial increase in precision when applied to the full Atlantic Canada region. It may prove useful in future hazard assessments, particularly of regions with highly heterogeneous Mc and relatively sparse catalogs.","PeriodicalId":498743,"journal":{"name":"Seismica","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134989461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-30DOI: 10.26443/seismica.v2i1.278
Mark Ireland, Guillermo Algarabel, Michael Steventon, Marcus Munafò
Geophysical research frequently makes use of agreed-upon methodologies, formally published software, and bespoke code to process and analyse data. The reliability and repeatability of these methods is vital in maintaining the integrity of research findings and thereby avoiding the dissemination of unreliable results. In recent years there has been increased attention on aspects of reproducibility, which includes data availability, across scientific disciplines. This review considers aspects of reproducibility of geophysical studies relating to their publication in peer reviewed journals. For 100 geophysics journals it considers the extent to which reproducibility in geophysics is the focus of published literature. For 20 geophysical journals it considers a) journal policies on the requirements for providing code, software, and data for submission; and b) the availability of data and software associated for 200 published journal articles. The findings show that: 1) between 1991 and 2021 there were 72 articles with reproducibility in the title and 417 with reliability, with an overall increase in the number of articles with reproducibility or reliability as the subject over the same period; 2) while 60% of journals have a definition of research data, only 20% of journals have a requirement for a data availability statement; and 3) despite ~86% of sampled journal articles including a data availability statement, only 54% of articles have the original data accessible via data repositories or web servers, and only 49% of articles name software used. It is suggested that despite journals and authors working towards improving the availability of data and software, frequently they are not identified, or easily accessible, therefore limiting the possibility of reproducing studies.
{"title":"How reproducible and reliable is geophysical research?","authors":"Mark Ireland, Guillermo Algarabel, Michael Steventon, Marcus Munafò","doi":"10.26443/seismica.v2i1.278","DOIUrl":"https://doi.org/10.26443/seismica.v2i1.278","url":null,"abstract":"Geophysical research frequently makes use of agreed-upon methodologies, formally published software, and bespoke code to process and analyse data. The reliability and repeatability of these methods is vital in maintaining the integrity of research findings and thereby avoiding the dissemination of unreliable results. In recent years there has been increased attention on aspects of reproducibility, which includes data availability, across scientific disciplines. This review considers aspects of reproducibility of geophysical studies relating to their publication in peer reviewed journals. For 100 geophysics journals it considers the extent to which reproducibility in geophysics is the focus of published literature. For 20 geophysical journals it considers a) journal policies on the requirements for providing code, software, and data for submission; and b) the availability of data and software associated for 200 published journal articles. The findings show that: 1) between 1991 and 2021 there were 72 articles with reproducibility in the title and 417 with reliability, with an overall increase in the number of articles with reproducibility or reliability as the subject over the same period; 2) while 60% of journals have a definition of research data, only 20% of journals have a requirement for a data availability statement; and 3) despite ~86% of sampled journal articles including a data availability statement, only 54% of articles have the original data accessible via data repositories or web servers, and only 49% of articles name software used. It is suggested that despite journals and authors working towards improving the availability of data and software, frequently they are not identified, or easily accessible, therefore limiting the possibility of reproducing studies.","PeriodicalId":498743,"journal":{"name":"Seismica","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135641860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：