Relocation of Light and Moderate‐Magnitude (M4–6) Seismicity Along the Central Mid‐Atlantic
Abstract We estimate precise relative epicentroid locations of earthquakes along the Mid‐Atlantic Ridge (MAR) between 12°N and 19°N using intermediate‐period Rayleigh and Love wave cross‐correlation measurements. We relocate 152 earthquakes with magnitudes ranging between 4.0 and 6.0 and when possib...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Wiley
2018-08-01
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| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2018GC007573 |
| _version_ | 1797351800844582912 |
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| author | K. Michael Cleveland Charles J. Ammon Jonas Kintner |
| author_facet | K. Michael Cleveland Charles J. Ammon Jonas Kintner |
| author_sort | K. Michael Cleveland |
| collection | DOAJ |
| description | Abstract We estimate precise relative epicentroid locations of earthquakes along the Mid‐Atlantic Ridge (MAR) between 12°N and 19°N using intermediate‐period Rayleigh and Love wave cross‐correlation measurements. We relocate 152 earthquakes with magnitudes ranging between 4.0 and 6.0 and when possible use P waveform modeling to estimate centroid depths. We compare surface‐wave locations to locations in the U.S. Geological Survey, Global Centroid Moment Tensor, and Pacific Marine Environmental Laboratory hydroacoustic catalogs (Smith et al., , https://doi.org/10.1029/2001GL013912) and demonstrate that surface‐wave based relative location techniques provide significant improvement on precision. Our analyses shift locations to more tectonically consistent alignments that correlate strongly with bathymetric features. Relocations along the Fifteen‐Twenty and Marathon Fracture Zones (FZs) move to within a few kilometers of the transform bathymetry. Events along ridge segments scatter over a distance of about 10–20 km perpendicular to the local plate boundary and most ridge‐segment seismicity clusters spatially. North of the Fifteen‐Twenty FZ, ridge events along several segments locate preferentially in the North American Plate, suggesting recent asymmetric seismic strain release and perhaps asymmetric spreading. Along the ridge between 13°N and 14°N, moderate‐magnitude seismic strain release concentrates in an area with two active oceanic core complexes (OCC) along the western rift boundary, but the largest events along this segment appear to occur along the eastern boundary rift valley faults and represent deformation opposite the OCC detachment surface processes. Precise moderate‐magnitude earthquake epicentroid locations for events that occurred over the last few decades complement the results of temporary seismometer deployments that have imaged microseismic activity along the MAR. |
| first_indexed | 2024-03-08T13:05:45Z |
| format | Article |
| id | doaj.art-f1851609200c441699756fc52ab4a3de |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-08T13:05:45Z |
| publishDate | 2018-08-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-f1851609200c441699756fc52ab4a3de2024-01-18T19:36:25ZengWileyGeochemistry, Geophysics, Geosystems1525-20272018-08-011982843285610.1029/2018GC007573Relocation of Light and Moderate‐Magnitude (M4–6) Seismicity Along the Central Mid‐AtlanticK. Michael Cleveland0Charles J. Ammon1Jonas Kintner2EES‐17: Geophysics Los Alamos National Laboratory Los Alamos NM USADepartment of Geosciences The Pennsylvania State University University Park PA USADepartment of Geosciences The Pennsylvania State University University Park PA USAAbstract We estimate precise relative epicentroid locations of earthquakes along the Mid‐Atlantic Ridge (MAR) between 12°N and 19°N using intermediate‐period Rayleigh and Love wave cross‐correlation measurements. We relocate 152 earthquakes with magnitudes ranging between 4.0 and 6.0 and when possible use P waveform modeling to estimate centroid depths. We compare surface‐wave locations to locations in the U.S. Geological Survey, Global Centroid Moment Tensor, and Pacific Marine Environmental Laboratory hydroacoustic catalogs (Smith et al., , https://doi.org/10.1029/2001GL013912) and demonstrate that surface‐wave based relative location techniques provide significant improvement on precision. Our analyses shift locations to more tectonically consistent alignments that correlate strongly with bathymetric features. Relocations along the Fifteen‐Twenty and Marathon Fracture Zones (FZs) move to within a few kilometers of the transform bathymetry. Events along ridge segments scatter over a distance of about 10–20 km perpendicular to the local plate boundary and most ridge‐segment seismicity clusters spatially. North of the Fifteen‐Twenty FZ, ridge events along several segments locate preferentially in the North American Plate, suggesting recent asymmetric seismic strain release and perhaps asymmetric spreading. Along the ridge between 13°N and 14°N, moderate‐magnitude seismic strain release concentrates in an area with two active oceanic core complexes (OCC) along the western rift boundary, but the largest events along this segment appear to occur along the eastern boundary rift valley faults and represent deformation opposite the OCC detachment surface processes. Precise moderate‐magnitude earthquake epicentroid locations for events that occurred over the last few decades complement the results of temporary seismometer deployments that have imaged microseismic activity along the MAR.https://doi.org/10.1029/2018GC007573Mid‐Atlantic Ridgeearthquake locationsurface wavesFifteen‐Twenty transformoceanic core complexes |
| spellingShingle | K. Michael Cleveland Charles J. Ammon Jonas Kintner Relocation of Light and Moderate‐Magnitude (M4–6) Seismicity Along the Central Mid‐Atlantic Geochemistry, Geophysics, Geosystems Mid‐Atlantic Ridge earthquake location surface waves Fifteen‐Twenty transform oceanic core complexes |
| title | Relocation of Light and Moderate‐Magnitude (M4–6) Seismicity Along the Central Mid‐Atlantic |
| title_full | Relocation of Light and Moderate‐Magnitude (M4–6) Seismicity Along the Central Mid‐Atlantic |
| title_fullStr | Relocation of Light and Moderate‐Magnitude (M4–6) Seismicity Along the Central Mid‐Atlantic |
| title_full_unstemmed | Relocation of Light and Moderate‐Magnitude (M4–6) Seismicity Along the Central Mid‐Atlantic |
| title_short | Relocation of Light and Moderate‐Magnitude (M4–6) Seismicity Along the Central Mid‐Atlantic |
| title_sort | relocation of light and moderate magnitude m4 6 seismicity along the central mid atlantic |
| topic | Mid‐Atlantic Ridge earthquake location surface waves Fifteen‐Twenty transform oceanic core complexes |
| url | https://doi.org/10.1029/2018GC007573 |
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