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

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.

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Tectonic controls on lake distribution in the Jalisco Block area (western Mexico) from Pliocene to present

Cenozoic tectonics and volcanism of Mexico ◽

10.1130/0-8137-2334-5.99 ◽

2000 ◽

Cited By ~ 3

Author(s):

François Michaud ◽

Françoise Gasse ◽

Jacques Bourgois ◽

Ordranoel Quintero

Keyword(s):

Western Mexico ◽

Jalisco Block ◽

Block Area

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Seismic imaging of the Cocos plate subduction zone system in central Mexico

Geochemistry Geophysics Geosystems ◽

10.1029/2012gc004033 ◽

2012 ◽

Vol 13 (7) ◽

pp. n/a-n/a ◽

Cited By ~ 29

Author(s):

YoungHee Kim ◽

Meghan S. Miller ◽

Frederick Pearce ◽

Robert W. Clayton

Keyword(s):

Subduction Zone ◽

Seismic Imaging ◽

Central Mexico ◽

Cocos Plate ◽

Plate Subduction

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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.

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