Seismic Site Amplification of the Cross of Opak River Fault at Yogyakarta, Indonesia, Under Ground Motions Generated by the Probabilistic Seismic Hazard Analysis

Seismic Site Amplification of the Cross of Opak River Fault at Yogyakarta, Indonesia, Under Ground Motions Generated by the Probabilistic Seismic Hazard Analysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Seismic Site Amplification of the Cross of Opak River Fault at Yogyakarta, Indonesia, Under Ground Motions Generated by the Probabilistic Seismic Hazard Analysis Widodo Pawirodikromo, Mochamad Teguh, Lalu Makrup, Mas Anggit, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7075085/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract This study investigates seismic site amplification along the Opak River fault in Yogyakarta, Indonesia, using ground motions generated through Probabilistic Seismic Hazard Analysis (PSHA). Four borehole locations—Andi Jaya, Masjid Btl, Sabdodadi, and Imogiri—were selected along the fault for site-specific analysis. Due to the absence of local earthquake records, synthetic ground motions were generated using a single-site PSHA approach. The bedrock-level Uniform Hazard Spectrum (UHS) was modified to represent the Maximum Considered Earthquake risk-targeted level (UHS MCEr) by incorporating the directivity factor (Dr) and the risk-targeted factor (R). The resulting UHS MCEr was used to match a real earthquake record spectrally—the 1981 Corinth event (Greece)—to generate bedrock accelerograms. These accelerograms were propagated through the soil layers at each site using DEEPSOIL for 1D site response analysis. The peak ground accelerations (PGAs) at the surface were found to be 0.347g, 0.344g, 0.341g, and 0.411g at Andi Jaya, Masjid Btl, Sabdodadi, and Imogiri, respectively, with the highest value observed at Imogiri due to its proximity to the fault. Peak-to-peak ground acceleration amplification factors were 1.66, 1.46, 1.30, and 1.49, while spectral amplification factors were 2.206, 1.650, 1.702, and 1.616, respectively. The average amplification values (1.477 for PGA and 1.794 for spectral) significantly exceed the amplification factor 1.09 specified in the current seismic code. This substantial amplification likely contributes to the high structural damage observed in areas intersected by the Opak fault. Full Text Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 21 Aug, 2025 Reviewers invited by journal 21 Aug, 2025 Editor assigned by journal 12 Jul, 2025 First submitted to journal 11 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7075085","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":503621935,"identity":"0e60c6fa-eb3a-41bf-9e2f-1d54fd5881fc","order_by":0,"name":"Widodo Pawirodikromo","email":"","orcid":"","institution":"Universitas Islam Indonesia","correspondingAuthor":false,"prefix":"","firstName":"Widodo","middleName":"","lastName":"Pawirodikromo","suffix":""},{"id":503621936,"identity":"78f30235-c20a-466e-bd05-028838dca350","order_by":1,"name":"Mochamad Teguh","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAvklEQVRIiWNgGAWjYPCCA3IMzIwNIBYPwwGCqpnBWoxJ15LYgLCRgAbdBv6DD7+23UnfcJy5geFHDYMMHyEtZgeYmY1l257lbjjM2MDYc4yBR5IILWzSkm2HwVoYeBsYeAyI0ML+G6gl3QBky18itbAxfmw7nADSwkycLYeZjaUZzh02nAnUcljmmAQRfjne+PDjj7LD8nznjz98+KbGxp5giIGihZkHygYqliCkHgIYfxCnbhSMglEwCkYqAAADS0F1ExqKBgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-2709-3975","institution":"Islamic University of Indonesia: Universitas Islam Indonesia","correspondingAuthor":true,"prefix":"","firstName":"Mochamad","middleName":"","lastName":"Teguh","suffix":""},{"id":503621937,"identity":"bba2375b-9941-4a33-89ef-1f696a664fb0","order_by":2,"name":"Lalu Makrup","email":"","orcid":"","institution":"Universitas Islam Indonesia","correspondingAuthor":false,"prefix":"","firstName":"Lalu","middleName":"","lastName":"Makrup","suffix":""},{"id":503621938,"identity":"aa4441f7-e73d-4bc5-bf55-9fb2b0569c7b","order_by":3,"name":"Mas Anggit","email":"","orcid":"","institution":"Universitas Islam Indonesia","correspondingAuthor":false,"prefix":"","firstName":"Mas","middleName":"","lastName":"Anggit","suffix":""},{"id":503621939,"identity":"3fadf4de-0e0c-4e18-81f5-389764275615","order_by":4,"name":"Bambang Suryo","email":"","orcid":"","institution":"Universitas Islam Indonesia","correspondingAuthor":false,"prefix":"","firstName":"Bambang","middleName":"","lastName":"Suryo","suffix":""}],"badges":[],"createdAt":"2025-07-08 12:57:50","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7075085/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7075085/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":90152797,"identity":"b3d84fbf-534a-4de6-b09b-becf7ec64422","added_by":"auto","created_at":"2025-08-29 07:33:39","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":807421,"visible":true,"origin":"","legend":"","description":"","filename":"RevisedSiteResponseAmplificationR.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7075085/v1_covered_36e782eb-7d86-4cd9-8ead-14f72d4e3355.pdf"}],"financialInterests":"","formattedTitle":"Seismic Site Amplification of the Cross of Opak River Fault at Yogyakarta, Indonesia, Under Ground Motions Generated by the Probabilistic Seismic Hazard Analysis","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"natural-hazards","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nhaz","sideBox":"Learn more about [Natural Hazards](https://www.springer.com/journal/11069)","snPcode":"11069","submissionUrl":"https://submission.nature.com/new-submission/11069/3","title":"Natural Hazards","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7075085/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7075085/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"This study investigates seismic site amplification along the Opak River fault in Yogyakarta, Indonesia, using ground motions generated through Probabilistic Seismic Hazard Analysis (PSHA). Four borehole locations—Andi Jaya, Masjid Btl, Sabdodadi, and Imogiri—were selected along the fault for site-specific analysis. Due to the absence of local earthquake records, synthetic ground motions were generated using a single-site PSHA approach. The bedrock-level Uniform Hazard Spectrum (UHS) was modified to represent the Maximum Considered Earthquake risk-targeted level (UHS MCEr) by incorporating the directivity factor (Dr) and the risk-targeted factor (R). The resulting UHS MCEr was used to match a real earthquake record spectrally—the 1981 Corinth event (Greece)—to generate bedrock accelerograms. These accelerograms were propagated through the soil layers at each site using DEEPSOIL for 1D site response analysis. The peak ground accelerations (PGAs) at the surface were found to be 0.347g, 0.344g, 0.341g, and 0.411g at Andi Jaya, Masjid Btl, Sabdodadi, and Imogiri, respectively, with the highest value observed at Imogiri due to its proximity to the fault. 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