Megathrust Slip Behavior for Great Earthquakes Along the Sumatra-Andaman Subduction Zone Mapped From Satellite GOCE Gravity Field Derivatives
During the last two decades, space geodesy allowed mapping accurately rupture areas, slip distribution, and seismic coupling by obtaining refined inversion models and greatly improving the study of great megathrust earthquakes. A better understanding of these phenomena involving large areas of hundr...
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| Language: | English |
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Frontiers Media S.A.
2021-02-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2020.581396/full |
| _version_ | 1819051048251162624 |
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| author | Orlando Álvarez Orlando Álvarez Stefanie Pechuan Canet Mario Gimenez Mario Gimenez Andrés Folguera |
| author_facet | Orlando Álvarez Orlando Álvarez Stefanie Pechuan Canet Mario Gimenez Mario Gimenez Andrés Folguera |
| author_sort | Orlando Álvarez |
| collection | DOAJ |
| description | During the last two decades, space geodesy allowed mapping accurately rupture areas, slip distribution, and seismic coupling by obtaining refined inversion models and greatly improving the study of great megathrust earthquakes. A better understanding of these phenomena involving large areas of hundreds of square kilometers came from the last gravity satellite mission that allowed detecting mass transfer through the Earth interior. In this work, we performed direct modeling of satellite GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) derived gravity gradients up to degree/order N = 200 of the harmonic expansion and then corrected this by the effect of topography. Cutting off the model up to this degree/order allows inferring mass heterogeneities located at an approximate depth of 31 km, just along the plate interface where most (but not all) significant slip occurs. Then, we compared the vertical gravity gradient to well-constrained coseismic slip models for three of the last major earthquakes along the Sunda interface. We analyzed seismic rupture behavior for recent and for historical earthquakes along this subduction margin and the relationship of the degree of interseismic coupling using the gravity signal. From this, we found that strong slip patches occurred along minima gravity gradient lobes and that the maximum vertical displacements were related quantitatively to the gravity-derived signal. The degree of interseismic coupling also presents a good correspondence to the vertical gravity gradient, showing an inverse relationship, with low degrees of coupling over regions of relatively higher density. This along-strike segmentation of the gravity signal agrees with the along-strike seismic segmentation observed from recent and historical earthquakes. The thermally controlled down-dip ending of the locked fault zone along central Sumatra also presented an inverse relationship with the density structure along the forearc inferred using our modeling. From this work, we inferred different mass heterogeneities related to persistent tectonic features along the megathrust and along the marine forearc, which may control strain accumulation and release along the megathrust. Combining these data with geodetical and seismological data could possibly delimit and monitor areas with a higher potential seismic hazard around the world. |
| first_indexed | 2024-12-21T11:57:44Z |
| format | Article |
| id | doaj.art-b68570ac8547447cb16c748837353510 |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-12-21T11:57:44Z |
| publishDate | 2021-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-b68570ac8547447cb16c7488373535102022-12-21T19:04:54ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632021-02-01810.3389/feart.2020.581396581396Megathrust Slip Behavior for Great Earthquakes Along the Sumatra-Andaman Subduction Zone Mapped From Satellite GOCE Gravity Field DerivativesOrlando Álvarez0Orlando Álvarez1Stefanie Pechuan Canet2Mario Gimenez3Mario Gimenez4Andrés Folguera5Instituto Geofísico y Sismológico Ing. Volponi, FCEFyN, Universidad Nacional de San Juan, San Juan, ArgentinaConsejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, ArgentinaConsejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, ArgentinaInstituto Geofísico y Sismológico Ing. Volponi, FCEFyN, Universidad Nacional de San Juan, San Juan, ArgentinaConsejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, ArgentinaIDEAN – Instituto de Estudios Andinos “Don Pablo Groeber”, Departamento de Cs. Geológicas, FCEN, Universidad de Buenos Aires, Buenos Aires, ArgentinaDuring the last two decades, space geodesy allowed mapping accurately rupture areas, slip distribution, and seismic coupling by obtaining refined inversion models and greatly improving the study of great megathrust earthquakes. A better understanding of these phenomena involving large areas of hundreds of square kilometers came from the last gravity satellite mission that allowed detecting mass transfer through the Earth interior. In this work, we performed direct modeling of satellite GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) derived gravity gradients up to degree/order N = 200 of the harmonic expansion and then corrected this by the effect of topography. Cutting off the model up to this degree/order allows inferring mass heterogeneities located at an approximate depth of 31 km, just along the plate interface where most (but not all) significant slip occurs. Then, we compared the vertical gravity gradient to well-constrained coseismic slip models for three of the last major earthquakes along the Sunda interface. We analyzed seismic rupture behavior for recent and for historical earthquakes along this subduction margin and the relationship of the degree of interseismic coupling using the gravity signal. From this, we found that strong slip patches occurred along minima gravity gradient lobes and that the maximum vertical displacements were related quantitatively to the gravity-derived signal. The degree of interseismic coupling also presents a good correspondence to the vertical gravity gradient, showing an inverse relationship, with low degrees of coupling over regions of relatively higher density. This along-strike segmentation of the gravity signal agrees with the along-strike seismic segmentation observed from recent and historical earthquakes. The thermally controlled down-dip ending of the locked fault zone along central Sumatra also presented an inverse relationship with the density structure along the forearc inferred using our modeling. From this work, we inferred different mass heterogeneities related to persistent tectonic features along the megathrust and along the marine forearc, which may control strain accumulation and release along the megathrust. Combining these data with geodetical and seismological data could possibly delimit and monitor areas with a higher potential seismic hazard around the world.https://www.frontiersin.org/articles/10.3389/feart.2020.581396/fullgreat earthquake rupture processmegathrust earthquakesGravity Field and Steady-State Ocean Circulation Explorer satellite dataseismic hazardsubduction zoneSumatra-Andaman earthquake |
| spellingShingle | Orlando Álvarez Orlando Álvarez Stefanie Pechuan Canet Mario Gimenez Mario Gimenez Andrés Folguera Megathrust Slip Behavior for Great Earthquakes Along the Sumatra-Andaman Subduction Zone Mapped From Satellite GOCE Gravity Field Derivatives Frontiers in Earth Science great earthquake rupture process megathrust earthquakes Gravity Field and Steady-State Ocean Circulation Explorer satellite data seismic hazard subduction zone Sumatra-Andaman earthquake |
| title | Megathrust Slip Behavior for Great Earthquakes Along the Sumatra-Andaman Subduction Zone Mapped From Satellite GOCE Gravity Field Derivatives |
| title_full | Megathrust Slip Behavior for Great Earthquakes Along the Sumatra-Andaman Subduction Zone Mapped From Satellite GOCE Gravity Field Derivatives |
| title_fullStr | Megathrust Slip Behavior for Great Earthquakes Along the Sumatra-Andaman Subduction Zone Mapped From Satellite GOCE Gravity Field Derivatives |
| title_full_unstemmed | Megathrust Slip Behavior for Great Earthquakes Along the Sumatra-Andaman Subduction Zone Mapped From Satellite GOCE Gravity Field Derivatives |
| title_short | Megathrust Slip Behavior for Great Earthquakes Along the Sumatra-Andaman Subduction Zone Mapped From Satellite GOCE Gravity Field Derivatives |
| title_sort | megathrust slip behavior for great earthquakes along the sumatra andaman subduction zone mapped from satellite goce gravity field derivatives |
| topic | great earthquake rupture process megathrust earthquakes Gravity Field and Steady-State Ocean Circulation Explorer satellite data seismic hazard subduction zone Sumatra-Andaman earthquake |
| url | https://www.frontiersin.org/articles/10.3389/feart.2020.581396/full |
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