Thermally-constrained fluid circulation and seismicity in the Lesser Antilles subduction zone

Ezenwaka, Kingsley; Marcaillou, Boris; Laigle, Mireille; Klingelhoëfer, Frauke; Lebrun, Jean‐Frédéric; Paulatto, M.; Biari, Y.; Rolandone, F.; Lucazeau, Francis; Heuret, Arnauld; Pichot, Thibaud; Bouquerel, H.

doi:10.1016/j.epsl.2022.117823

Cited by 3 publications

(1 citation statement)

References 81 publications

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“…Several researchers have noted that slab dehydration may have elevated pore pressures in the source region (Bie et al 2022;Ezenwaka et al 2022;Hicks et al 2023). It has also been recognised that reduced fault strength due to increased pore pressure can induce rupture on non-optimal fault planes, thus leading to diverse focal mechanism solutions (e.g.…”

Section: Discussionmentioning

confidence: 99%

Complex rupture evolution of the 2007 Martinique earthquake: a non-double-couple event in the Caribbean Sea

Ohara¹,

Yagi²,

Okuwaki³

2023

Preprint

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A large non-double-couple component of a tectonic earthquake indicates that its rupture likely was complex and likely involved multiple faults. Detailed source models of such earthquakes can add to our understanding of earthquake source complexity. The 2007 Martinique earthquake in the Caribbean Sea is one of the largest recent earthquakes with a known large non-double-couple component. It was an intermediate depth intraslab earthquake within the South America plate where it is subducting beneath the Caribbean plate. We applied potency density tensor inversion (PDTI) to teleseismic P waves generated by the 2007 Martinique earthquake to model its source processes and focal mechanism distribution. We identified two focal mechanisms: a strike-slip mechanism with a north–south T axis, and a down-dip extension (DDE) mechanism with an east–west T axis. Rupture by the DDE mechanism was predominant in the northern part of the source region and strike-slip rupture in the southern part. These two focal mechanisms had approximately parallel P axes and approximately orthogonal T axes. The seismic moments released by both types of rupture were almost equal. These results indicate that the 2007 Martinique earthquake had a large non-double-couple component. We identified five sub-events with two predominant directions of rupture propagation: two strike-slip sub-events propagated to the southeast and three DDE sub-events propagated to the east. Although the directions of propagation were consistent for each focal mechanism, each sub-event appears to have occurred in isolation. For example, the rupture of one DDE sub-event propagated from the edge of the source region back towards the hypocentre. Complex ruptures that include multiple sub-events may be influenced by high pore fluid pressure associated with slab dehydration. Our results show that PDTI can produce stable estimates of complex seismic source processes and provide useful information about the sources of complex intermediate depth intraslab earthquakes for which fault geometry assumptions are difficult.

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Section: Discussionmentioning

confidence: 99%

Complex rupture evolution of the 2007 Martinique earthquake: a non-double-couple event in the Caribbean Sea

Ohara¹,

Yagi²,

Okuwaki³

2023

Preprint

View full text Add to dashboard Cite

show abstract

Diverse magma storage and major and volatile magma composition: What are the implications on the eruptive style across a volcanic arc? An example of the Lesser Antilles Arc

Metcalfe

Moune

Komorowski

et al. 2023

Earth-Science Reviews

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Complex rupture evolution of the 2007 Martinique earthquake: a non-double-couple event in the Caribbean Sea

Ohara,

Yagi,

Okuwaki

2024

Geophysical Journal International

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Summary A large non-double-couple component of a tectonic earthquake indicates that its rupture likely was complex and likely involved multiple faults. Detailed source models of such earthquakes can add to our understanding of earthquake source complexity. The 2007 Martinique earthquake in the Caribbean Sea is one of the largest recent earthquakes with a known large non-double-couple component. It was an intermediate depth intraslab earthquake within the South American plate where it is subducting beneath the Caribbean plate. We applied potency density tensor inversion (PDTI) to teleseismic P waves generated by the 2007 Martinique earthquake to model its source processes and focal mechanism distribution. We identified two focal mechanisms: a strike-slip mechanism with a north–south tension axis (T axis), and a down-dip extension (DDE) mechanism with an east–west T axis. Rupture by the DDE mechanism was predominant in the northern part of the source region and strike-slip rupture in the southern part. These two focal mechanisms had approximately parallel pressure axes (P axes) and approximately orthogonal T axes. The seismic moments released by both types of rupture were almost equal. These results indicate that the 2007 Martinique earthquake had a large non-double-couple component. We identified five sub-events with two predominant directions of rupture propagation: two strike-slip sub-events propagated to the southeast and three DDE sub-events propagated to the east. Although the directions of propagation were consistent for each focal mechanism, each sub-event appears to have occurred in isolation. For example, the rupture of one DDE sub-event propagated from the edge of the source region back towards the hypocentre. Complex ruptures that include multiple sub-events may be influenced by high pore fluid pressure associated with slab dehydration. Our results show that PDTI can produce stable estimates of complex seismic source processes and provide useful information about the sources of complex intermediate depth intraslab earthquakes for which fault geometry assumptions are difficult.

show abstract

Thermally-constrained fluid circulation and seismicity in the Lesser Antilles subduction zone

Cited by 3 publications

References 81 publications

Complex rupture evolution of the 2007 Martinique earthquake: a non-double-couple event in the Caribbean Sea

Complex rupture evolution of the 2007 Martinique earthquake: a non-double-couple event in the Caribbean Sea

Diverse magma storage and major and volatile magma composition: What are the implications on the eruptive style across a volcanic arc? An example of the Lesser Antilles Arc

Complex rupture evolution of the 2007 Martinique earthquake: a non-double-couple event in the Caribbean Sea

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