Apparent Non-Double-Couple Components as Artifacts of Moment Tensor Inversion
Compilations of earthquake moment tensors from global and regional catalogs find pervasive non-double-couple (NDC) components with a mean deviation from a double-couple (DC) source of around 20%. Their distributions vary only slightly with magnitude, faulting mechanism, or geologic environments. Thi...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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McGill University
2024-04-01
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| Series: | Seismica |
| Subjects: | |
| Online Access: | https://seismica.library.mcgill.ca/article/view/1157 |
| _version_ | 1797213905110433792 |
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| author | Boris Rösler Seth Stein Adam Ringler Jiří Vackář |
| author_facet | Boris Rösler Seth Stein Adam Ringler Jiří Vackář |
| author_sort | Boris Rösler |
| collection | DOAJ |
| description | Compilations of earthquake moment tensors from global and regional catalogs find pervasive non-double-couple (NDC) components
with a mean deviation from a double-couple (DC) source of around 20%. Their distributions vary only slightly with magnitude, faulting mechanism, or geologic environments. This consistency suggests thatfor most earthquakes, especially smaller ones whose rupture processes are expected to be simpler, the NDC components are largely artifacts of the moment tensor inversion procedure. This possibility is also supported by the fact that NDC components for individual earthquakes with Mw<6.5 are only weakly correlated between
catalogs. We explore this possibility by generating synthetic seismograms for the double-couple components of earthquakes around the
world using one Earth model and inverting them with a different Earth model. To match the waveforms with a different Earth model, the inversion changes the mechanisms to include a substantial NDC component while largely preserving the fault geometry (DC component). The resulting NDC components have a size and distribution similar to those reported for the earthquakes in the Global Centroid Moment Tensor (GCMT) catalog. The fact that numerical experiments replicate general features of the pervasive NDC components reported in moment tensor catalogs implies that these components are largely artifacts of the inversions not adequately accounting for the effects of laterally varying Earth structure. |
| first_indexed | 2024-04-24T11:05:42Z |
| format | Article |
| id | doaj.art-38560ffc67584ff1a289aabb7bf5e154 |
| institution | Directory Open Access Journal |
| issn | 2816-9387 |
| language | English |
| last_indexed | 2024-04-24T11:05:42Z |
| publishDate | 2024-04-01 |
| publisher | McGill University |
| record_format | Article |
| series | Seismica |
| spelling | doaj.art-38560ffc67584ff1a289aabb7bf5e1542024-04-11T16:55:38ZengMcGill UniversitySeismica2816-93872024-04-013110.26443/seismica.v3i1.11571152Apparent Non-Double-Couple Components as Artifacts of Moment Tensor InversionBoris Rösler0https://orcid.org/0000-0001-8596-5650Seth Stein1Adam Ringler2https://orcid.org/0000-0002-9839-4188Jiří Vackář3https://orcid.org/0000-0002-4696-2454Northwestern UniversityNorthwestern UniversityUnited States Geological Survey (USGS)Czech Academy of SciencesCompilations of earthquake moment tensors from global and regional catalogs find pervasive non-double-couple (NDC) components with a mean deviation from a double-couple (DC) source of around 20%. Their distributions vary only slightly with magnitude, faulting mechanism, or geologic environments. This consistency suggests thatfor most earthquakes, especially smaller ones whose rupture processes are expected to be simpler, the NDC components are largely artifacts of the moment tensor inversion procedure. This possibility is also supported by the fact that NDC components for individual earthquakes with Mw<6.5 are only weakly correlated between catalogs. We explore this possibility by generating synthetic seismograms for the double-couple components of earthquakes around the world using one Earth model and inverting them with a different Earth model. To match the waveforms with a different Earth model, the inversion changes the mechanisms to include a substantial NDC component while largely preserving the fault geometry (DC component). The resulting NDC components have a size and distribution similar to those reported for the earthquakes in the Global Centroid Moment Tensor (GCMT) catalog. The fact that numerical experiments replicate general features of the pervasive NDC components reported in moment tensor catalogs implies that these components are largely artifacts of the inversions not adequately accounting for the effects of laterally varying Earth structure.https://seismica.library.mcgill.ca/article/view/1157non-double-couple componentmoment tensormoment tensor inversionsynthetic seismograms |
| spellingShingle | Boris Rösler Seth Stein Adam Ringler Jiří Vackář Apparent Non-Double-Couple Components as Artifacts of Moment Tensor Inversion Seismica non-double-couple component moment tensor moment tensor inversion synthetic seismograms |
| title | Apparent Non-Double-Couple Components as Artifacts of Moment Tensor Inversion |
| title_full | Apparent Non-Double-Couple Components as Artifacts of Moment Tensor Inversion |
| title_fullStr | Apparent Non-Double-Couple Components as Artifacts of Moment Tensor Inversion |
| title_full_unstemmed | Apparent Non-Double-Couple Components as Artifacts of Moment Tensor Inversion |
| title_short | Apparent Non-Double-Couple Components as Artifacts of Moment Tensor Inversion |
| title_sort | apparent non double couple components as artifacts of moment tensor inversion |
| topic | non-double-couple component moment tensor moment tensor inversion synthetic seismograms |
| url | https://seismica.library.mcgill.ca/article/view/1157 |
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