{"title":"Machine learning-based aftershock seismicity of the 2015 Gorkha earthquake controlled by flat-ramp geometry and a tear fault","authors":"Yeyang Kuang , Jiangtao Li","doi":"10.1016/j.eqs.2024.05.002","DOIUrl":null,"url":null,"abstract":"<div><div>The Main Himalayan Thrust (MHT), where the 2015 <em>M</em><sub>W</sub>7.8 Gorkha earthquake occurred, features the most seismicity of any structure in Nepal. The structural complexity of the MHT makes it difficult to obtain a definitive interpretation of deep seismogenic structures. The application of new methods and data in this region is necessary to enhance local seismic hazard analyses. In this study, we used a well-designed machine learning-based earthquake location workflow (LOC-FLOW), which incorporates machine learning phase picking, phase association, absolute location, and double-difference relative location, to process seismic data collected by the Hi-CLIMB and NAMASTE seismic networks. We built a high-precision earthquake catalog of both the quiet-period and aftershock seismicity in this region. The seismicity distribution suggests that the quiet-period seismicity (388 events) was controlled by a mid-crustal ramp and the aftershock seismicity (12,669 events) was controlled by several geological structures of the MHT. The higher-level detail of the catalogs derived from this machine learning method reveal clearer structural characteristics, showing how the flat-ramp geometry and a possible duplex structure affect the depth distribution of the seismic events, and how a tear fault changes this distribution along strike.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 1","pages":"Pages 17-32"},"PeriodicalIF":1.2000,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Earthquake Science","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1674451924000582","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"Earth and Planetary Sciences","Score":null,"Total":0}
引用次数: 0
Abstract
The Main Himalayan Thrust (MHT), where the 2015 MW7.8 Gorkha earthquake occurred, features the most seismicity of any structure in Nepal. The structural complexity of the MHT makes it difficult to obtain a definitive interpretation of deep seismogenic structures. The application of new methods and data in this region is necessary to enhance local seismic hazard analyses. In this study, we used a well-designed machine learning-based earthquake location workflow (LOC-FLOW), which incorporates machine learning phase picking, phase association, absolute location, and double-difference relative location, to process seismic data collected by the Hi-CLIMB and NAMASTE seismic networks. We built a high-precision earthquake catalog of both the quiet-period and aftershock seismicity in this region. The seismicity distribution suggests that the quiet-period seismicity (388 events) was controlled by a mid-crustal ramp and the aftershock seismicity (12,669 events) was controlled by several geological structures of the MHT. The higher-level detail of the catalogs derived from this machine learning method reveal clearer structural characteristics, showing how the flat-ramp geometry and a possible duplex structure affect the depth distribution of the seismic events, and how a tear fault changes this distribution along strike.
期刊介绍:
Earthquake Science (EQS) aims to publish high-quality, original, peer-reviewed articles on earthquake-related research subjects. It is an English international journal sponsored by the Seismological Society of China and the Institute of Geophysics, China Earthquake Administration.
The topics include, but not limited to, the following
● Seismic sources of all kinds.
● Earth structure at all scales.
● Seismotectonics.
● New methods and theoretical seismology.
● Strong ground motion.
● Seismic phenomena of all kinds.
● Seismic hazards, earthquake forecasting and prediction.
● Seismic instrumentation.
● Significant recent or past seismic events.
● Documentation of recent seismic events or important observations.
● Descriptions of field deployments, new methods, and available software tools.
The types of manuscripts include the following. There is no length requirement, except for the Short Notes.
【Articles】 Original contributions that have not been published elsewhere.
【Short Notes】 Short papers of recent events or topics that warrant rapid peer reviews and publications. Limited to 4 publication pages.
【Rapid Communications】 Significant contributions that warrant rapid peer reviews and publications.
【Review Articles】Review articles are by invitation only. Please contact the editorial office and editors for possible proposals.
【Toolboxes】 Descriptions of novel numerical methods and associated computer codes.
【Data Products】 Documentation of datasets of various kinds that are interested to the community and available for open access (field data, processed data, synthetic data, or models).
【Opinions】Views on important topics and future directions in earthquake science.
【Comments and Replies】Commentaries on a recently published EQS paper is welcome. The authors of the paper commented will be invited to reply. Both the Comment and the Reply are subject to peer review.