Steep subduction geometry of the Rivera Plate beneath the Jalisco Block in western Mexico

We performed 3-D seismic tomography using teleseismic arrival time at Southwest Mexico. The Mexican subduction zone results from successive fragmentation events that affected the ancient Farallon plate as various segments of the East Pacific rise approached the paleo-trench off western North America. The complexity in this region is related to two subducting oceanic plates, the Rivera and Cocos plates, that have different ages, compositions, convergence velocities and subduction dip angles. In this study, we compared the 3-D raytracing tomography model with finite frequency tomography model. Final models show the differences in amplitude and pattern between the raytracing and finite frequency. 3D raytracing models produced sharper images of fast velocity structures in the mantle. The deeper slabs are more coherent and show less broadening with depth than using 1D finite frequency kernels. However, although the finite frequency and 3-D ray tracing models show some differences in amplitude and pattern, the overall agreement of the models supports the interpretation of Yang et al. (2009) that slab rollback is occurring in South Western Mexico. One possible different interpretation between the raytracing and finite frequency theory results concerns the deep structure of the Rivera slab. The finite frequency models show that the Rivera slab is clearly observable at a depth of about 300km but fades away at greater depths. However, the 3-D ray tracing model shows a clear fast velocity band down to a depth of 400 km and thus our model does not support a slab tear of the Rivera plate above 400 km depth

Download Full-text

Gravity evidence for shaping of the crustal structure of the Ameca graben (Jalisco block northern limit). Western Mexico

Journal of South American Earth Sciences ◽

10.1016/j.jsames.2017.12.014 ◽

2018 ◽

Vol 82 ◽

pp. 215-230 ◽

Cited By ~ 1

Author(s):

Miguel Angel Alatorre-Zamora ◽

José Oscar Campos-Enríquez ◽

Emilia Fregoso-Becerra ◽

Luis Quintanar-Robles ◽

Roberto Toscano-Fletes ◽

...

Keyword(s):

Crustal Structure ◽

Northern Limit ◽

Western Mexico ◽

Jalisco Block

Download Full-text

Analysis of the Seismicity in the Jalisco Block from June to December 2015

Seismological Research Letters ◽

10.1785/0220190107 ◽

2019 ◽

Cited By ~ 1

Author(s):

Tatiana Marín‐Mesa ◽

Francisco J. Núñez‐Cornú ◽

Carlos Suárez‐Plascencia

Keyword(s):

Seismogenic Zone ◽

Regional Studies ◽

Northern Coast ◽

Jalisco Block ◽

Seismic Swarms ◽

Using Data ◽

Dip Angle ◽

Seismic Networks ◽

Rivera Plate ◽

Hypocentral Distribution

ABSTRACT We present the first study of seismicity in the region of the Jalisco Block using data recorded by the Jalisco Seismic Accelerometric Telemetric Network between June and December 2015. During this period, 683 local earthquakes with magnitudes between 1.0<ML≤4.0 were identified and relocated with Hypo71PC. From this catalog, we identify a heterogeneous hypocentral distribution with six continental crustal seismogenic areas. We also observed seismicity associated with the subduction process that extends 180 km from the Mesoamerican trench, which suggests an estimated dip angle of the slab between 22° and 31°. A subtle dip also suggests oblique subduction toward the Colima rift zone and bending of the Rivera plate. These observations are in agreement with previous partial regional studies using local seismic networks. Two seismic swarms were observed in this period, one in the Bahia de Banderas seismogenic zone, and a second in the Guadalajara Metropolitan zone. We note two areas on the northern coast of Jalisco with meager rates of seismicity.

Download Full-text

Multichannel Seismic Imaging of the Rivera Plate Subduction at the Seismogenic Jalisco Block Area (Western Mexican Margin)

Pure and Applied Geophysics ◽

10.1007/s00024-016-1331-y ◽

2016 ◽

Vol 173 (10-11) ◽

pp. 3575-3594 ◽

Cited By ~ 2

Author(s):

Rafael Bartolome ◽

Estefanía Górriz ◽

Juanjo Dañobeitia ◽

Diego Cordoba ◽

David Martí ◽

...

Keyword(s):

Seismic Imaging ◽

Jalisco Block ◽

Block Area ◽

Rivera Plate ◽

Plate Subduction

Download Full-text

The Extended Continental Crust West of Islas Marías (Mexico)

Frontiers in Earth Science ◽

10.3389/feart.2021.666272 ◽

2021 ◽

Vol 9 ◽

Author(s):

Diana Núñez ◽

Jorge A. Acosta-Hernández ◽

Felipe de Jesús Escalona-Alcázar ◽

Simone Pilia ◽

Francisco Javier Núñez-Cornú ◽

...

Keyword(s):

Continental Crust ◽

Contact Region ◽

Complex Structure ◽

Sedimentary Basins ◽

North American Plate ◽

Seismic Profiles ◽

Tectonic Structures ◽

Jalisco Block ◽

Rivera Plate ◽

Plate Subduction

The crustal structure around the Islas Marías Archipelago has been debated for a long time. An important unresolved question is where the Rivera-North American plate subduction ends and the Tamayo fracture zone begins, from SE to NW. Results from the TsuJal project have shed light on the northwesternmost part of the Jalisco block structure. It is now clear that Sierra de Cleofas and the Islas Marías Escarpment comprise the northwestern continuation of the Middle America trench. However, other questions remain. In this paper, we present the structure of the shallow and deep crust and the upper mantle of the Islas Marías western region through the integration of multichannel seismic reflection, wide-angle seismic bathymetric and seismicity data, including records of an amphibious seismic network, OBS, and portable seismic stations, purposely deployed for this project, providing an onshore-offshore transect of 310 km length. Our findings disclose new evidence of the complex structure of the Rivera plate that dips 8°–9° underneath the NW Jalisco block as revealed by two seismic profiles parallel to the Islas Marías Escarpment. Moreover, we find five sedimentary basins and active normal faults at the edges of tectonic structures of the E-W oriented West Ranges and the N-S trending Sierra de Cleofas. Furthermore, the Sierra de Cleofas is the beginning of the active subduction of the Rivera plate beneath North America. The oceanic crust thickens and submerges towards the south while is coupled with the continental crust, from 6 km at the northern ends of the seismic profiles to 15 km in the contact region and 24 km at the coast and southern ends of them. The continental Moho was not fully characterized because of the geometry of the seismic transects, but a low-velocity layer associated with Rivera Plate subduction was observed beneath the Jalisco Block. Our results constrain the complexity of the area and reveal new structural features from the oceanic to continental crust and will be pivotal to assess geohazards in this area.

Download Full-text