DOCSLIB.ORG

Attenuation of Coda Waves in the Central Region of the Gulf of California, México

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Attenuation of Coda Waves in the Central Region of the Gulf of California, México GEOFÍSICA INTERNACIONAL (2017) 56-2: 137-145 ORIGINAL PAPER Attenuation of Coda Waves in the Central Region of the Gulf of California, México Héctor E. Rodríguez-Lozoya, Tonatiuh Domínguez R., Luis Quintanar Robles, Armando Aguilar Meléndez, Héctor E. Rodríguez-Leyva, Wenseslao Plata Rocha and Fernando García Páez Received: January 06, 2016; accepted: October 25, 2016; published on line: April 01, 2017 Resumen frecuencias de 1 a 7 Hz. El valor y la alta QO dependencia de la frecuencia están de acuerdo Se analizan las ondas de coda de eventos con los valores reportados para otras regiones registrados por la red sísmica de NARS que caracterizadas por una alta actividad tectónica. cuenta con instrumentos instalados a lo largo Con base en la distribución de estaciones de ambas márgenes del Golfo de California, respecto a las fuentes, se definieron dos México, para estimar atenuación . Se utilizó Qc subregiones (norte y sur). Se calcularon modelo de dispersión simple de Sato (1977) los valores de y se correlacionaron con QC para ventanas tiempo de 20 a 25 segundos la tectónica y morfología de cada zona. comenzando en dos veces el tiempo de viaje Se observa una mayor atenuación en la de la onda S. Se analizaron eventos registrados región sur que puede ser atribuida a que entre 2003 y 2007 ocurridos en la región esa zona esté más fracturada dado que los central del Golfo de California. Las distancias eventos sísmicos mayores ocurren de la fuente-receptor analizadas son entre 40 y 500 zona centro del Golfo de California hacia el km. Suponiendo una relación de dependencia sur. Por otro lado, la corteza de la zona sur de de la frecuencia de la forma Qc QC (f) es de menor espesor que la zona norte. = a, los valores promedio encontrados QO f fueron de = 83±3 y una dependencia de QO Palabras clave: Atenuación de coda, atenuación- la frecuencia a de 1.06±0.03 en el rango de frecuencia, Golfo de California, Mexico. H. E. Rodríguez-Lozoya* A. Aguilar Meléndez H. E. Rodríguez-Leyva Universidad Veracruzana F. García Páez Campus Poza Rica, México Facultad de Ingeniería Universidad Autónoma de Sinaloa, México W. Plata Rocha *Corresponding author: [email protected] Facultad de Ciencias de la Tierra y el Espacio Universidad Autónoma de Sinaloa, México T. Domínguez R. Centro Universitario de Estudios e Investigación en Vulcanología Universidad de Colima, México L. Quintanar Robles Instituto de Geofísica Universidad Nacional Autónoma de México Ciudad Universitaria Delegación Coyoacán 04510 Mexico CDMX, México 137 H. E. Rodríguez-Lozoya, et al. Abstract value and the high frequency dependency QO agree with the values of other regions Coda waves were analyzed from events characterized by a high tectonic activity. recorded by NARS seismic network deployed Based on source-station distribution two along both margins of the Gulf of California, subregions (north and south) were defined. Mexico, to estimate coda attenuation Qc. Sato’s values were calculated and correlated QC (1977) single scattering model was used for a with tectonics and morphology of each area. coda window of 20 to 25 s beginning at twice The observed higher attenuation in the south the S-wave travel time. Events recorded from region can be attributed to the fact that south 2003 to 2007 located in the central region of region is more fractured since the greater the Gulf of California were analyzed. earthquakes occur in central to south Gulf of Source-to-receiver distances are between 40 California and the oceanic crust is reported to and 500 km. Assuming a power law of the be thinner in the southern region. form = a, values were averaged QC (f) QO f QC and value of = 83±3 and a frequency- a QO Key words: Coda attenuation, attenuation- dependence α value of 1.06±0.03 in the frequency, Gulf of California, Mexico. frequency range from 1 to 7 Hz was obtained. Introduction Data from 6 stations of the NARS-Baja network (Network of Autonomously Recording The Gulf of California, Mexico, is a complex Seismographs of Baja California) installed tectonic zone where the peninsula of Baja by Utrecht University, CALTECH and CICESE California is separating from the continent. This (Centro de Investigación Científica y Educación active zone has generated moderate earthquakes Superior de Ensenada Baja California, México) which have affected cities on both sides of the during 2002 were used. This region was chosen gulf. In 2012, an M6.0 earthquake affected due to its implication in terms of civil protection the city of Los Mochis, where damages in the for the cities on both sides of the Gulf. The regional hospital were reported. Last earthquake correlation of the results with the morphology occurred on September, 2015 (MW6.7). and tectonics of the region is also presented. Social and economic effects resulting from Tectonic Setting and Seismicity earthquakes can be reduced through seismic risk analysis. The elaboration of good quality The Gulf of California forms an oblique- hazard maps is required. To do this, studies divergent boundary between the Pacific and of source characteristics and wave propagation North America plates. Relative motion between are essential. Attenuation is an important the peninsula of Baja California and North factor to such studies. America plate in the southern gulf is about 46 mm/yr (Plattner et al., 2007). It consists of Attenuation of seismic waves has been a system of linked transform faults and short widely studied in different regions around the spreading centers forming basins (Lonsdale, world since Aki and Chouet (1975) and Sato 1989). Deformation accommodates in oblique (1977) introduced their theories on coda waves faults to the north and transform faults to attenuation (Q). Different tectonic regions the south (Fenby and Gastil, 1991; Nagy and around the world (e.g., volcanic, active, stable) Stock, 2000). Northern basins are shallower have been characterized by their Q-1 values than those to the center and southern basins (Pulli, 1984; Jin et al., 1985; Wiggins-Grandison (Curray et al., 1982; Lonsdale, 1989; Persaud and Havskov, 2004, among others). In Mexico et al., 2003). there are attenuation studies mostly for the south and southeastern for the subduction In the north zone of the Gulf, an incipient zones of the Rivera and Cocos plates (Castro spreading center begins in the Wagner basin and Munguía, 1993; Ordaz and Singh 1992; (Persaud et al., 2003) developed from Cerro Prieto Domínguez et al., 2003, among others) and for and Wagner transform faults, and ending in the the northwestern zone of Mexico for the Gulf south with the East Pacific Rise which corresponds of California region (Domínguez et al., 1997; to the northern limit of the Rivera plate. Castro et al., 2008). Lonsdale (1989) suggested the presence of In the present study, Sato’s formulation a transitional crust at the Guaymas basin in the (Sato, 1977) was used to estimate at the middle sector of the Gulf of California. In this QC central zone of the Gulf of California. location, there is a high rate of sedimentation, 138 VOLUME 56 NUMBER 2 GEOFÍSICA INTERNACIONAL Figure 1. Tectonic setting and location of used seismic stations (triangles) and analyzed earthquakes (circles). White squares indicate main cities in the area. Red circles indicate events with Mw >5. TAFZ (Tosco-Abreajos fault zone), EPR (East Pacific Rise). which promoted the development of a basin of scatterers in an infinite volume and cross- containing sills and altered sediments. sectional area s. The density of energy in terms of root mean square (rms) amplitude, scattered Most of the seismicity is distributed in the by the inhomogeneities on the surface of an NW–SE direction along the axis of the Gulf ellipsoid whose foci are the source, and the of California, following a linear trend that, receiver can be expressed as from north to south, steps southward near the main basins (Wagner, Delfin, Guaymas, 12/ 12/ 1 Ω()ω ∆f []K()α −ω tQ/ 2 Carmen, Farallon, Pescadero, and Alarcon) A(,rt\)ω = e , and spreading centers. Seismicity in the ω []2πσL r northern zone has low magnitude (Castro et (1) al., 2007) but increases to the south reaching magnitudes of M>6 such as the 2010 and where A is the rms amplitude of the coda 2015 earthquakes that occurred near (south) wave, W(w) is the total energy radiated by parallel 25º N, or the 1992 earthquake (M7.0), the source within a frequency band, r is the which is the greater earthquake ever recorded distance between the source and the receiver, in this zone (Pacheco and Sykes, 1992). 1 (a) = [(a+1)/(a−1)] and a = , t is the K a ln t/ts Only good quality data (high signal/noise elapsed time of the coda wave, is the elapsed ts ratio) was used from five years recording which time of the S wave, both measured from the included 4 moderate events (M>5) and their earthquake origin time. L = 1/Ns is the mean aftershocks (Figure 1). free path. Method Usually (1) is expressed as the linear function Sato’s (1977) formulation was used to estimate Q through measurements of the amplitude C ln[]Ar(,t \)ω decay of coda waves with time. The model =−lnCf(/π Qt) assumes a source embedded in an infinite []K()α (2) medium populated by a random distribution APRIL - JUNE 2017 139 H. E. Rodríguez-Lozoya, et al. Figure 2. Example of an event used for calculation. Records correspond to the 2003/03/12 earthquake Qc (Mw6.3). Table 1: Velocity model. to a 24 bit resolution recorder. 20 samples per second are recorded. For this reason the analysis Vp Vs Density Thickness was restricted to frequencies below 10 Hz.
Load more

Recommended publications
  • Why Did the Southern Gulf of California Rupture So Rapidly?—Oblique Divergence Across Hot, Weak Lithosphere Along a Tectonically Active Margin
    Why did the Southern Gulf of California rupture so rapidly?—Oblique divergence across hot, weak lithosphere along a tectonically active margin breakup, is mainly dependent on the thermal structure, crust- Paul J. Umhoefer, Geology Program, School of Earth Sciences & Environmental Sustainability, Northern Arizona University, al thickness, and crustal strength of the lithosphere when Flagstaff, Arizona 86011, USA; [email protected] rifting begins (e.g., Buck, 2007), as well as forces at the base of the lithosphere and far-field plate interactions (Ziegler and Cloetingh, 2004). ABSTRACT Continental rupture at its two extremes creates either large Rifts in the interior of continents that evolve to form large ocean basins or small and narrow marginal seas depending oceans typically last for 30 to 80 m.y. and longer before com- largely on the tectonic setting of the rift. Rupture of a conti- plete rupture of the continent and onset of sea-floor spreading. nent that creates large oceans most commonly initiates as A distinct style of rifts form along the active tectonic margins of rifts in old, cold continental lithosphere or within former continents, and these rifts more commonly form marginal seas large collisional belts in the interior of large continents, part and terranes or continental blocks or slivers that are ruptured of the process known as the Wilson Cycle (Wilson, 1966). away from their home continent. The Gulf of California and the Rupture to create narrow marginal seas commonly occurs in Baja California microplate make up one of the best examples active continental margins and results in the formation of of the latter setting and processes.
    [Show full text]
  • Patricia Persaud
    A bottom-driven mechanism for distributed faulting in the Gulf of California Rift Patricia Persaud1, Eh Tan2, Juan Contreras3 and Luc Lavier4 2017 GeoPRISMS Theoretical and Experimental Institute on Rift Initiation and Evolution [email protected], Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803; 2 Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan; 3 Centro de Investigación Científca y de Educación Superior de Ensenada, Ensenada, BC, Mexico; 4 University of Texas Austin, Institute for Geophysics, Austin, TX 78712 Introduction Modeling strain partitioning and distribution of deformation in Application to the Northern Gulf Observations in the continent-ocean transition of the Gulf • Our model with an obliquity of 0.7, and linear basal velocity of California (GOC) show multiple oblique-slip faults oblique rifts boundary conditions reveals a delocalized fault pattern of distributed in a 200x70 km2 area (Fig. 4). In contrast, north contemporaneously active faults, multiple rift basins and and south of this broad pull-apart structure, major transform variable fault dips representative of faulting in the N. Gulf. faults accommodate plate motion. We propose that the FIG. 9 • The r=0.7 model is able to predict the broad geometrical mechanism for distributed faulting results from the boundary arrangement of the two Upper Delfn, Lower Delfn and conditions present in the GOC, where basal shear is Wagner basins as segmented basins with tilted fault blocks, distributed between the southernmost fault of the San and multiple oblique-slip bounding faults characteristic of Andreas system and the Ballenas Transform fault. FIG. 8 incomplete strain-partitioning. We also confrm with our We hypothesize that in oblique-extensional settings numerical results that numerous oblique-slip faults whether deformation is partitioned in a few dip-slip and accommodate slip in the study area instead of throughgoing strike-slip faults, or in numerous oblique-slip faults may large-offset transform faults.
    [Show full text]
  • Field Trip Log Gulf of California Rift System: Laguna Salda-Valles Chico-San Feli- Pe, Baja California, México
    Geos, Vol. 28, No. 1, Septiembre, 2008 FIELD TRIP LOG GULF OF CALIFORNIA RIFT SYSTEM: LAGUNA SALDA-VALLES CHICO-SAN FELI- PE, BAJA CALIFORNIA, MÉXICO Francisco Suárez-Vidal Departamento de Geologia División de Ciencias de la Tierra CICESE Oblique rifts, in which rift margins are oblique to the direction of continental separation, are reasonably common in mo- dern record, e.g. the Red Sea and Gulf of Aden, the Tanganyika-Malawi-Rukwa rifts and the Gulf of California (McKenzie et al., 1970; Rosendhal et al., 1992; Stoke and Hodges, 1989; Manighetti et al., 1998; Nagy and Stock, 2000; Persaud, P., 2003; Persaud, et al., 2003). Although, how the oblique rift evolves is not well known. Oblique rifting remain poorly understand relative to those orthogonal rifts, where the rift margins are approximately perpendicular to the extension direction, and to strike-slip system (Axen and Fletcher, 1998). The Gulf of California is perhaps the best modern example of oblique continental rifting where we can study the pro- cesses of such rifting as they lead to the interplate transfer of a continental fragment. This area presents unique op- portunities for understanding key processes at transtensional plate margins, which is important for energy and mineral exploration, as well as for interpretation of tectonics ancient continental margins (Umhoefer and Dorsey, 1997). One of the main features along the length of the gulf is the fault system which connects active basins (incipient spreading centers) from south to north (Fig 1). Two main structural regions are defined. From the mouth of the gulf to the latitude of the Tiburon and Angel de La Guardia Islands several basins bathymetrically are well expressed, among them; the Pescaderos, Farallon, Carmen, Guaymas, San Pedro Martir and Salsipudes Basins.
    [Show full text]
  • Bathymetry and Active Geological Structures in the Upper Gulf of California Luis G
    BOLETÍN DE LA SOCIEDAD GEOLÓ G ICA MEXICANA VOLU M EN 61, NÚ M . 1, 2009 P. 129-141 Bathymetry and active geological structures in the Upper Gulf of California Luis G. Alvarez1*, Francisco Suárez-Vidal2, Ramón Mendoza-Borunda2, Mario González-Escobar3 1 Departamento de Oceanografía Física, División de Oceanología. 2 Departamento de Geología, División de Ciencias de la Tierra. 3 Departamento de Geofísica Aplicada, División de Ciencias de la Tierra. Centro de Investigación Científica y de Educación Superior de Ensenada, B.C. Km 107 carretera Tijuana-Ensenada, Ensenada, Baja California, México, 22860. * Corresponding author: E-mail: [email protected] Abstract Bathymetric surveys made between 1994 and 1998 in the Upper Gulf of California revealed that the bottom relief is dominated by narrow, up to 50 km long, tidal ridges and intervening troughs. These sedimentary linear features are oriented NW-SE, and run across the shallow shelf to the edge of Wagner Basin. Shallow tidal ridges near the Colorado River mouth are proposed to be active, while segments in deeper water are considered as either moribund or in burial stage. Superposition of seismic swarm epicenters and a seismic reflection section on bathymetric features indicate that two major ridge-troughs structures may be related to tectonic activity in the region. Off the Sonora coast the alignment and gradient of the isobaths matches the extension of the Cerro Prieto Fault into the Gulf. A similar gradient can be seen over the west margin of the Wagner Basin, where in 1970 a seismic swarm took place (Thatcher and Brune, 1971) overlapping with a prominent ridge-trough structure in the middle of the Upper Gulf.
    [Show full text]
  • UNIVERSITY of CALIFORNIA, SAN DIEGO Marine Geophysical Study
    UNIVERSITY OF CALIFORNIA, SAN DIEGO Marine Geophysical Study of Cyclic Sedimentation and Shallow Sill Intrusion in the Floor of the Central Gulf of California A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Oceanography by Jared W. Kluesner Committee in Charge: Professor Peter Lonsdale, Chair Professor Paterno Castillo Professor Graham Kent Professor Falko Kuester Professor Michael Tryon Professor Edward Winterer 2011 Copyright Jared Kluesner, 2011 All rights reserved. The Dissertation of Jared W. Kluesner is approved, and it is acceptable in quality and in form for publication on microfilm and electronically: Chair University of California, San Diego 2011 iii To my parents, Tony and Donna Kluesner and my grandfather James Kluesner iv "...Let us go, we said, into the Sea of Cortez, realizing that we become forever a part of it" The Log from the Sea of Cortez John Steinbeck v TABLE OF CONTENTS Signature Page ...................................................................................... iii Dedication.............................................................................................. iv Epigraph ................................................................................................ v Table of Contents .................................................................................. vi List of Figures ........................................................................................ ix Acknowledgments ................................................................................
    [Show full text]
  • Redalyc.Attenuation of Coda Waves in the Central Region of the Gulf Of
    Geofísica Internacional ISSN: 0016-7169 [email protected] Universidad Nacional Autónoma de México México Rodríguez-Lozoya, Héctor E.; Domínguez R., Tonatiuh; Quintanar Robles, Luis; Aguilar Meléndez, Armando; Rodríguez-Leyva, Héctor E.; Plata Rocha, Wenseslao; García Páez, Fernando Attenuation of Coda Waves in the Central Region of the Gulf of California, México Geofísica Internacional, vol. 56, núm. 2, enero-marzo, 2017, pp. 137-145 Universidad Nacional Autónoma de México Distrito Federal, México Available in: http://www.redalyc.org/articulo.oa?id=56850598001 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative GEOFÍSICA INTERNACIONAL (2017) 56-2: 137-145 ORIGINAL PAPER Attenuation of Coda Waves in the Central Region of the Gulf of California, México Héctor E. Rodríguez-Lozoya, Tonatiuh Domínguez R., Luis Quintanar Robles, Armando Aguilar Meléndez, Héctor E. Rodríguez-Leyva, Wenseslao Plata Rocha and Fernando García Páez Received: January 06, 2016; accepted: October 25, 2016; published on line: April 01, 2017 Resumen frecuencias de 1 a 7 Hz. El valor y la alta QO dependencia de la frecuencia están de acuerdo Se analizan las ondas de coda de eventos con los valores reportados para otras regiones registrados por la red sísmica de NARS que caracterizadas por una alta actividad tectónica. cuenta con instrumentos instalados a lo largo Con base en la distribución de estaciones de ambas márgenes del Golfo de California, respecto a las fuentes, se definieron dos México, para estimar atenuación .
    [Show full text]
  • Nature of the Crust in the Northern Gulf of California and Salton Trough GEOSPHERE, V
    Research Paper THEMED ISSUE: Anatomy of Rifting: Tectonics and Magmatism in Continental Rifts, Oceanic Spreading Centers, and Transforms GEOSPHERE Nature of the crust in the northern Gulf of California and Salton Trough GEOSPHERE, v. 15, no. 5 Jolante W. van Wijk1, Samuel P. Heyman1,2, Gary J. Axen1, and Patricia Persaud3 1Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, New Mexico 87801, USA https://doi.org/10.1130/GES02082.1 2SM Energy, 1775 Sherman Street, Suite 1200, Denver, Colorado 80203, USA 3Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell-Kniffen, Baton Rouge, Louisiana 70803, USA 9 figures; 2 tables CORRESPONDENCE: [email protected] ■ ABSTRACT elevation 34°N (m) 1 Salton Sea CITATION: van Wijk, J.W., Heyman, S.P., Axen, G.J., 2400 and Persaud, P., 2019, Nature of the crust in the north- In the southern Gulf of California, the generation of new oceanic crust 1600 2 3 800 ern Gulf of California and Salton Trough: Geosphere, has resulted in linear magnetic anomalies and seafloor bathymetry that are Cerro Prieto v. 15, no. 5, p. 1598–1616, https://doi.org/10.1130 32°N 0 characteristic of active seafloor-spreading systems. In the northern Gulf of ˗800 AZ NM /GES02082.1. Mexico California and the onshore (southeastern California, USA) Salton Trough region, ˗1600 Wagner Basin ˗2400 a thick sedimentary package overlies the crystalline crust, masking its nature, 4 Science Editor: Shanaka de Silva 30°N ˗3200 North American plate Guest Associate Editor: Carolina Pagli and linear magnetic anomalies are absent.
    [Show full text]
  • Space Geodetic Observation of the Deformation Cycle Across the Ballenas Transform, Gulf of California Christina Plattner University of Miami
    University of South Florida Scholar Commons School of Geosciences Faculty and Staff School of Geosciences Publications 8-2015 Space Geodetic Observation of the Deformation Cycle across the Ballenas Transform, Gulf of California Christina Plattner University of Miami Rocco Malservisi University of South Florida, [email protected] Falk Amelung University of Miami Timothy H. Dixon University of South Florida, [email protected] Matthias Hackl Ludwig‐Maximilians Universität München See next page for additional authors Follow this and additional works at: https://scholarcommons.usf.edu/geo_facpub Part of the Earth Sciences Commons Scholar Commons Citation Plattner, Christina; Malservisi, Rocco; Amelung, Falk; Dixon, Timothy H.; Hackl, Matthias; Verdecchia, Alessandro; Lonsdale, Peter; Suarez-Vidal, Francisco; and Gonzalez-Garcia, Javier, "Space Geodetic Observation of the Deformation Cycle across the Ballenas Transform, Gulf of California" (2015). School of Geosciences Faculty and Staff Publications. 1531. https://scholarcommons.usf.edu/geo_facpub/1531 This Article is brought to you for free and open access by the School of Geosciences at Scholar Commons. It has been accepted for inclusion in School of Geosciences Faculty and Staff ubP lications by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Authors Christina Plattner, Rocco Malservisi, Falk Amelung, Timothy H. Dixon, Matthias Hackl, Alessandro Verdecchia, Peter Lonsdale, Francisco Suarez-Vidal, and Javier Gonzalez-Garcia This article is available at Scholar Commons: https://scholarcommons.usf.edu/geo_facpub/1531 PUBLICATIONS Journal of Geophysical Research: Solid Earth RESEARCH ARTICLE Space geodetic observation of the deformation cycle 10.1002/2015JB011959 across the Ballenas Transform, Gulf of California Key Points: Christina Plattner1,2, Rocco Malservisi3, Falk Amelung2, Timothy H.
    [Show full text]
  • The Structural Evolution of Pull-Apart Basins in Response to Changes in Plate Motion
    Louisiana State University LSU Digital Commons Faculty Publications Department of Geology and Geophysics 4-1-2021 The structural evolution of pull-apart basins in response to changes in plate motion Georgios Pavlos Farangitakis Durham University Ken J.W. McCaffrey Durham University Ernst Willingshofer Utrecht University Mark B. Allen Durham University Lara M. Kalnins The University of Edinburgh See next page for additional authors Follow this and additional works at: https://digitalcommons.lsu.edu/geo_pubs Recommended Citation Farangitakis, G., McCaffrey, K., Willingshofer, E., Allen, M., Kalnins, L., van Hunen, J., Persaud, P., & Sokoutis, D. (2021). The structural evolution of pull-apart basins in response to changes in plate motion. Basin Research, 33 (2), 1603-1625. https://doi.org/10.1111/bre.12528 This Article is brought to you for free and open access by the Department of Geology and Geophysics at LSU Digital Commons. It has been accepted for inclusion in Faculty Publications by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. Authors Georgios Pavlos Farangitakis, Ken J.W. McCaffrey, Ernst Willingshofer, Mark B. Allen, Lara M. Kalnins, Jeroen van Hunen, Patricia Persaud, and Dimitrios Sokoutis This article is available at LSU Digital Commons: https://digitalcommons.lsu.edu/geo_pubs/1329 Received: 27 July 2020 | Revised: 5 November 2020 | Accepted: 12 November 2020 DOI: 10.1111/bre.12528 EAGE RESEARCH ARTICLE The structural evolution of pull-apart basins in response to changes in plate motion Georgios-Pavlos Farangitakis1 | Ken J. W. McCaffrey1 | Ernst Willingshofer2 | Mark B. Allen1 | Lara M. Kalnins3 | Jeroen van Hunen1 | Patricia Persaud4 | Dimitrios Sokoutis2,5 1Department of Earth Sciences, Durham University, Durham, United Kingdom Abstract 2Department of Earth Sciences, Utrecht Pull-apart basins are structural features linked to the interactions between strike-slip University, Utrecht, the Netherlands and extensional tectonics.
    [Show full text]
  • Source Characteristics of the Mw 6.2 Loreto Earthquake of 12 March 2003 That Occurred in a Transform Fault in the Middle Of
    Bulletin of the Seismological Society of America, Vol. 95, No. 2, pp. 419–430, April 2005, doi: 10.1785/0120030227 Source Characteristics of the Mw 6.2 Loreto Earthquake of 12 March 2003 that Occurred in a Transform Fault in the Middle of the Gulf of California, Mexico by Leobardo Lo´pez-Pineda and Cecilio J. Rebollar Abstract We analyzed the Loreto earthquake of 12 March 2003 Mw 6.2, which occurred in the transform fault that joins the Guaymas and Carmen Basins in the middle of the Gulf of California. This event was recorded by a network of autono- mous continuously recording broadband seismographs located over the Baja Cali- fornia Peninsula, Sonora, and Sinaloa states of Mexico. The main event was located km. A foreshock of magnitude 2 ע at 26.615Њ N and 111.09Њ W, at a depth of 5.0 4.2 was recorded and located at 26.580Њ N and 111.011Њ W. We located 35 after- shocks, 20% of them were located in the rupture area of the mainshock consistent with a nearly vertical right-lateral strike-slip fault with a northwest–southeast trend. Rupture propagation derived from waveform analysis indicated that the rupture prop- agated from northwest to southeast. Most of the aftershocks occurred southeaster of the main event. From the statistical analysis of 333 aftershocks we calculated a b- value of 0.68. Focal depth and fault geometry were estimated from body-wave form modeling of P and S waves. Synthetics were calculated using Herrmann’s (1987) reflectivity code with a triangular source time function of 6 sec.
    [Show full text]
  • Systematic Heat Flow Measurements Across the Wagner Basin, Northern
    Earth and Planetary Science Letters 479 (2017) 340–353 Contents lists available at ScienceDirect Earth and Planetary Science Letters www.elsevier.com/locate/epsl Systematic heat flow measurements across the Wagner Basin, northern Gulf of California ∗ Florian Neumann a, Raquel Negrete-Aranda b, , Robert N. Harris c, Juan Contreras b, John G. Sclater d, Antonio González-Fernández b a Posgrado en Ciencias de la Tierra, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, BC, 22864, Mexico b Departamento de Geología, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, BC, 22864, Mexico c College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA d Geosciences Research Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, 92093-0220, USA a r t i c l e i n f o a b s t r a c t Article history: A primary control on the geodynamics of rifting is the thermal regime. To better understand the Received 1 March 2017 geodynamics of rifting in the northern Gulf of California we systematically measured heat-flow across the Received in revised form 13 September Wagner Basin, a tectonically active basin that lies near the southern terminus of the Cerro Prieto fault. 2017 The heat flow profile is 40 km long, has a nominal measurement spacing of ∼1 km, and is collocated Accepted 14 September 2017 with a seismic reflection profile. Heat flow measurements were made with a 6.5-m violin-bow probe. Available online 6 October 2017 Although heat flow data were collected in shallow water, where there are significant temporal variations Editor: R.
    [Show full text]
  • Shear Wave Splitting and Mantle Flow in Mexico: What Have We Learned?
    GEOFÍSICA INTERNACIONAL (2017) 56-2: 187-217 ORIGINAL PAPER Shear Wave Splitting and Mantle Flow in Mexico: What Have we Learned? Raúl W. Valenzuela* and Gerardo León Soto Received: November 15, 2016; accepted: December 08, 2016; published on line: April 01, 2017 Resumen con un énfasis en las zonas de subducción. Una justificación importante para el estudio de la El presente artículo es un resumen y análisis anisotropía sísmica es que permite conocer las de los estudios de partición de ondas características del flujo en el manto superior transversales (shear wave splitting) para así como su relación con procesos tectónicos. el manto superior que se han realizado en México tiene muchos y diversos ambientes México durante la última década. Cuando una tectónicos. Algunos de ellos se encuentran onda sísmica entra en un medio anisótropo actualmente activos y otros lo fueron en el se parte (o se separa), esto quiere decir que pasado, pero en cualquier caso han dejado se producen una onda rápida y otra lenta. Se su marca en la forma de anisotropía sísmica. necesitan dos parámetros para cuantificar la Esto ha dado lugar a una gran variedad anisotropía. Dichos parámetros son la dirección de mecanismos para producir el flujo del de polarización rápida y el tiempo de retardo manto. De manera general la presentación entre la onda rápida y la lenta. Se presenta se ha organizado en las siguientes regiones: un ejemplo de la aplicación de la técnica península de Baja California, la región Mexicana empleando la fase SKS ya que la mayoría de Occidental de Cuencas y Sierras, el norte y las observaciones usan datos telesísmicos.
    [Show full text]