Mantle wedge hydration in Nicaragua from local earthquake tomography

Dinc, A. Nilay; Rabbel, Wolfgang; Flueh, Ernst R.; Taylor, Waldo

doi:10.1111/j.1365-246x.2011.05041.x

Cited by 26 publications

(23 citation statements)

References 75 publications

(204 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As such it can be expected that it differs from its surrounding rock units rheologically as well as in terms of seismic velocity. Early as well as recent seismic investigations have shown that ≥15% seismic velocity reduction, corresponding to ≥20% serpentinization, can easily be expected in fractured oceanic lithosphere [e.g., White et al , 1984; Calvert and Potts , 1985; Ivandic et al , 2010; Dinc et al 2011]. …”

Section: Discussionmentioning

confidence: 99%

Seismicity near the slip maximum of the 1960 Mw 9.5 Valdivia earthquake (Chile): Plate interface lock and reactivation of the subducted Valdivia Fracture Zone

Dzierma¹,

Thorwart²,

Rabbel³

et al. 2012

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

Understanding the processes behind subduction‐related hazards is an important responsibility and major challenge for the Earth sciences. Few areas demonstrate this as clearly as south‐central Chile, where some of the largest earthquakes in human history have occurred. We present the first observation of local seismicity in the Villarrica region (39°–40°S), based on a temporary local network of 55 stations installed from the Chilean coast into the Argentinian back‐arc for one year. While consistent with the Chilean national catalog (SSN), our results allow us to observe smaller magnitudes with a completeness of about 2.0 and image the geometry of the Wadati‐Benioff Zone from the Chile Trench down to 200 km. Offshore, a gap in interplate seismicity is observed in the region of the 1960 Valdivia earthquake slip. Above the interface, two offshore seismicity clusters possibly indicate ongoing stress relaxation. In the subducting Nazca Plate, we find a prominent seismicity cluster along the extrapolated trace of the oceanic Valdivia Fracture Zone (VFZ). The seismicity cluster is observed between 70 and 130 km depth and comprises mainly strike‐slip events. It indicates weakening and reactivation of the major VFZ by dehydration of oceanic crust and mantle. Interpreting the subducted VFZ section as a localized reservoir of potential fluid release offers an explanation for the Villarrica volcanic complex that is located above the reactivated VFZ and shows the highest volcanic activity in South America. Crustal seismicity is observed near Puyehue volcano, which recently started to erupt (June 2011).

show abstract

Section: Discussionmentioning

confidence: 99%

Seismicity near the slip maximum of the 1960 Mw 9.5 Valdivia earthquake (Chile): Plate interface lock and reactivation of the subducted Valdivia Fracture Zone

Dzierma¹,

Thorwart²,

Rabbel³

et al. 2012

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Unusually deep earthquakes have been identified both in subduction zones (e.g., DINC et al, 2011) and in rift zones (e.g., LINDENFELD AND RÜ MP-KER, 2011). The generation of such earthquakes was related to the presence of water in these geodynamical systems (dehydration reactions in the subducting plates) or to deep magmatic processes in the rift structures.…”

Section: Discussionmentioning

confidence: 99%

New Seismic and Tomography Data in the Southern Part of the Harghita Mountains (Romania, Southeastern Carpathians): Connection with Recent Volcanic Activity

Popa

Rădulian

Szakács

et al. 2011

Pure Appl. Geophys.

View full text Add to dashboard Cite

The southern part of the southeastern Carpathians represents the site of the most recent volcanic eruptions of the entire Carpathian-Pannonian region. The products of these eruptions range from 42 to 10 Ka radiocarbon ages in the South Harghita Mountains (high K calc-alkaline rocks with adakite-like features), and at 1.2-0.6 Ma K-Ar ages in the Perşani Mountains (alkali basalts). They were emplaced in a post-collisional regime. Ciomadul volcano is located at the southernmost part of the NW-SE oriented Cȃlimani-Gurghiu-Harghita range crossing the inner part of the southeastern Carpathians and in the rough proximity of the Vrancea seismic zone (at ca. 60 km toward NW). Its magma generation is attributed to geodynamic events closely related to the seismogenic area. A number of particular geophysical and geochemical features located in the study region, including (1) the abrupt attenuation of the seismic waves originating from the Vrancea intermediate-depth foci, (2) the most intense heat-flow anomaly in Romania, (3) the most prominent 3 He/ 4 He anomaly measured in natural ''postvolcanic'' gas emanations, are all in favor of the hypothesis of a still existing hot local magma chamber. Data acquired during recent seismic monitoring of the Vrancea zone and its neighborhoods suggest an enhancement of the local seismicity beneath the southern edge of the South Harghita Mts., both at crustal and subcrustal levels. At the same time, recent tomography images obtained using local earthquake data correlate well with the presence of a vertically extended low-velocity zone coming from the upper mantle to the assumed magmatic chambers located in the crust. The present data, supporting the presence of an active crustal magma chamber beneath Ciomadul, allow us to consider that future volcanic activity at this volcano cannot be discarded.

show abstract

“…Seismic structure beneath Costa Rica and Nicaragua has been investigated in a number of tomographic studies based on data acquired by several temporary networks [e.g., Colombo et al , 1997; Protti et al , 1999; Yao et al , 1999; Sallarès et al , 2000; Quintero and Kissling , 2001; Husen et al , 2003; Arroyo et al , 2009; Dinc et al , 2010, 2011]. Most of the different authors applied independent approaches.…”

Section: Introductionmentioning

confidence: 99%

“…The crust and lithospheric mantle of the overriding plate shows regionally variable velocities which could be associated with major tectonic units and local structure such as subducting seamounts. A pronounced minimum of velocity and increased Vp/Vs ratios are found in southern Nicaragua suggesting a significant hydration of the mantle wedge [ Dinc et al , 2010, 2011].…”

Section: Introductionmentioning

confidence: 99%

Arc‐parallel shear deformation and escape flow in the mantle wedge of the Central America subduction zone: Evidence from P wave anisotropy

Rabbel

Koulakov

Dinc³

et al. 2011

Geochem Geophys Geosyst

View full text Add to dashboard Cite

[1] The P wave anisotropy of the crust and uppermost mantle has been determined in two separate areas of the continental margin of Central America covering offshore and onshore parts of southern Nicaragua and northern and central Costa Rica. Our study is based on traveltime data from local earthquakes recorded with three combined onshore and offshore seismic networks that had been deployed in three half-year intervals between 2002 and 2006. The P wave traveltime data have been tomographically inverted in terms of an elliptical anisotropic P wave velocity distribution. In the upper crust beneath Costa Rica, the seismic anisotropy is of the order of 2%-5% and locally strongly variable in orientation corresponding to the complicated tectonic structure. In contrast, the upper mantle beneath both study regions shows stronger anisotropy of the order of 5%-10% and a more coherent orientation of the axis of fast P wave velocity that varies systematically on regional scales: The upper mantle of the incoming oceanic plate is characterized by a trench-normal orientation of the fast P wave velocity axis presumably corresponding to mineral alignment (lattice preferred orientation LPO) in transport direction. This pattern is corroded in the uppermost part of the subduction zone, possibly by the influence of bending-related trench-parallel faults and serpentinization that can overprint or annihilate the LPO anisotropy. The upper mantle of the overriding plate and mantle wedge shows a clear trench-parallel orientation of the fast P wave velocity axis. The anisotropy is stronger in Nicaragua than in southern central Costa Rica (factor of 2 orders of magnitude). The development of a stronger anisotropy in the Nicaragua could be driven by a change in the stress regime from compressional in southern Costa Rica to transpressional in Nicaragua corresponding to a change from near-orthogonal subduction in the SE to oblique subduction and slab retreat in the NW. From a comparison with S/SKS wave, GPS, and geochemical observations follows that the most likely explanation for the observed pattern of P wave anisotropy in the mantle wedge is LPO caused by a trench-parallel shear deformation and/or NW oriented escape flow originating in the compressional zone near the Cocos Ridge collision area.

show abstract

Mantle wedge hydration in Nicaragua from local earthquake tomography

Cited by 26 publications

References 75 publications

Seismicity near the slip maximum of the 1960 Mw 9.5 Valdivia earthquake (Chile): Plate interface lock and reactivation of the subducted Valdivia Fracture Zone

Seismicity near the slip maximum of the 1960 Mw 9.5 Valdivia earthquake (Chile): Plate interface lock and reactivation of the subducted Valdivia Fracture Zone

New Seismic and Tomography Data in the Southern Part of the Harghita Mountains (Romania, Southeastern Carpathians): Connection with Recent Volcanic Activity

Arc‐parallel shear deformation and escape flow in the mantle wedge of the Central America subduction zone: Evidence from P wave anisotropy

Contact Info

Product

Resources

About