{"id":3633,"date":"2016-01-24T22:21:57","date_gmt":"2016-01-25T06:21:57","guid":{"rendered":"http:\/\/earthjay.com\/?p=3633"},"modified":"2016-01-24T22:21:57","modified_gmt":"2016-01-25T06:21:57","slug":"earthquake-report-mediterranean","status":"publish","type":"post","link":"https:\/\/earthjay.com\/?p=3633","title":{"rendered":"Earthquake Report: Mediterranean!"},"content":{"rendered":"<p>We just had a M 6.1 earthquake and a few aftershocks (M 4-5) in the western Mediterranean,<br \/>\nHere is the <a href=\"http:\/\/earthquake.usgs.gov\/earthquakes\/eventpage\/us10004gy9#general_summary\" target=\"_blank\" rel=\"noopener\">USGS website for this earthquake<\/a>.<br \/>\nHere is a map showing the 5 largest earthquakes as circles.<br \/>\nThere is a legend that shows how moment tensors can be interpreted. Moment tensors are graphical solutions of seismic data that show two possible fault plane solutions. One must use local tectonics, along with other data, to be able to interpret which of the two possible solutions is correct. The legend shows how these two solutions are oriented for each example (Normal\/Extensional, Thrust\/Compressional, and Strike-Slip\/Shear). There is more about <a href=\"http:\/\/earthquake.usgs.gov\/learn\/glossary\/?term=moment%20tensor\" target=\"_blank\" rel=\"noopener\">moment tensors<\/a> and <a href=\"http:\/\/earthquake.usgs.gov\/learn\/topics\/beachball.php\" target=\"_blank\" rel=\"noopener\">focal mechanisms<\/a> at the USGS.<br \/>\n<a href=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/20160125_gibraltar_interpretation.pdf\" target=\"_blank\" rel=\"noopener\"><br \/>\n<img decoding=\"async\" src=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/20160125_gibraltar_interpretation.jpg\" width=\"100%\" alt=\"\" \/><\/a><br \/>\nFor more on the graphical representation of moment tensors and focal mechnisms, check this <a href=\"http:\/\/www.iris.edu\/hq\/programs\/education_and_outreach\/animations\/25\" target=\"_blank\" rel=\"noopener\">IRIS<\/a> video out:<br \/>\n<iframe loading=\"lazy\" width=\"420\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/MomVOkyDdLo\" frameborder=\"0\" allowfullscreen><\/iframe><br \/>\nBased on the mapping presented by <a href=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/gracia_etal_2012_acoustic_seismic_imaging_adra_fault_alboran_sea.pdf\" target=\"_blank\" rel=\"noopener\">Gracia et al (2012)<\/a>, <a href=\"https:\/\/www.researchgate.net\/publication\/230309107_The_Alboran_Sea_Western_Mediterranean_revisited_with_a_view_from_the_Moroccan_Margin\" target=\"_blank\" rel=\"noopener\">Casciello et al. (2016)<\/a>, and the bathymetry, this earthquake may have ruptured one of the northeast striking structures that are shown in the lower left part of the <a href=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/gracia_etal_2012_acoustic_seismic_imaging_adra_fault_alboran_sea.pdf\" target=\"_blank\" rel=\"noopener\">Gracia et al. (2012)<\/a> map. Therefore I interpret this earthquake to be a left-lateral strike-slip earthquake.<br \/>\nHere is a close up of Gracia et al. (2012) Figure 1. I provide their caption below in blockquote.<br \/>\n<a href=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/gracia_etal_2012_acoustic_seismic_imaging_adra_fault_alboran_sea_fig_1.JPG\" target=\"_blank\" rel=\"noopener\"><br \/>\n<img decoding=\"async\" src=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/gracia_etal_2012_acoustic_seismic_imaging_adra_fault_alboran_sea_fig_1.JPG\" width=\"100%\" alt=\"\" \/><\/a><\/p>\n<blockquote><p>\nFigure 1. Schematic geological map of the Westernmost Mediterranean highlighting the position of the Alboran Domain enclosed between Iberia and northwest Africa. Its metamorphic rocks compose the floor of the western Alboran Sea and form the inner zones of the Betics and Rif mountain chains.\n<\/p><\/blockquote>\n<p>Here is the Casciello et al (2016) figure showing their tectonic interpretation. Figure is their map and Figure 2 is an earlier tectonic interpretation (Andrieux et al., 1971).  I provide their caption below in blockquote.<br \/>\n<a href=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/Figure-1-Schematic-geological-map-of-the-Westernmost-Mediterranean-highlighting-the.png\" target=\"_blank\" rel=\"noopener\"><br \/>\n<img decoding=\"async\" src=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/Figure-1-Schematic-geological-map-of-the-Westernmost-Mediterranean-highlighting-the.png\" width=\"100%\" alt=\"\" \/><\/a><\/p>\n<blockquote><p>\nFig. 1. Regional topographic and bathymetric map of the southeast Iberian margin constructed from digital grids released by SRTM-3, IEO bathymetry (Ballesteros et al., 2008; Mu\u02dcnoz et al., 2008) and MEDIMAP multibeam compilation (MediMap et al., 2008) at \u0018 90m grid-size. Epicenters of the largest historical earthquakes (MSK Intensity>VIII) in the region are depicted by a white star (I.G.N., 2010). Grey arrows pointing opposite each other show the direction of convergence between the Eurasian and African plates from NUVEL1 model (DeMets et al., 2010). The black outlined rectangle depicts the study area presented in Fig. 2. BSF: Bajo Segura Fault; AMF: Alhama de Murcia Fault, PF: Palomares Fault, CF: Carboneras Fault, YF: Yusuf Fault, AR: Alboran Ridge. Inset: Plate tectonic setting and main geodynamic domains of the south Iberian margin along the boundary between the Eurasian and African Plates.\n<\/p><\/blockquote>\n<p><a href=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/Figure-3-Original-model-by-Andrieux-et-al-1971-to-explain-the-formation-of-the.png\" target=\"_blank\" rel=\"noopener\"><img decoding=\"async\" src=\"http:\/\/earthjay.com\/earthquakes\/20160125_gibraltar\/Figure-3-Original-model-by-Andrieux-et-al-1971-to-explain-the-formation-of-the.png\" alt=\"\" \/><\/a><\/p>\n<blockquote><p>\nFig. 3. Original model by Andrieux et al. (1971) to explain the formation of the Gibraltar Arc. The Alboran microplate would resist the eastward movement of the European and African plates, which are<br \/>\nforced by oceanic expansion in the Atlantic, causing the formation of the Betic-Rif chains.\n<\/p><\/blockquote>\n<ul>\nReferences:<\/p>\n<li>Andrieux et al., 1971., Sur un modele explicatif de l\u2019Arc de Gibraltar in Earth and Planetary Science Letters, v. 12, p. 191\u2013198.<\/li>\n<li>Casciello., et al., 2016. <a href=\"https:\/\/www.researchgate.net\/publication\/230309107_The_Alboran_Sea_Western_Mediterranean_revisited_with_a_view_from_the_Moroccan_Margin\" target=\"_blank\" rel=\"noopener\">The Alboran Domain in the Western Mediterranean evolution: the birth of a concept<\/a> in: SERANNE M. et al., Eds, Lithosphere dynamics and sedimentary basins: The circum-Mediteranean basins and analogues. \u2013 Bull. Soc. g\u00e9ol. Fr. 186, sp issue (in press).<\/li>\n<li>Gracia, E. et al., 2012. <a href=\"http:\/\/www.nat-hazards-earth-syst-sci.net\/12\/3255\/2012\/\" target=\"_blank\" rel=\"noopener\">Acoustic and seismic imaging of the Adra Fault (NE Alboran Sea): in search of the source of the 1910 Adra earthquake<\/a> in Natural Hazqards and Earth System Sciences, v. 12, 3255-3267.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<div class=\"entry-summary\">\nWe just had a M 6.1 earthquake and a few aftershocks (M 4-5) in the western Mediterranean, Here is the USGS website for this earthquake. Here is a map showing the 5 largest earthquakes as circles. There is a legend&hellip;\n<\/div>\n<div class=\"link-more\"><a href=\"https:\/\/earthjay.com\/?p=3633\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &ldquo;Earthquake Report: Mediterranean!&rdquo;<\/span>&hellip;<\/a><\/div>\n","protected":false},"author":3,"featured_media":3634,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0},"categories":[50,5,6,52,7,9,27,33,37],"tags":[],"aioseo_notices":[],"jetpack_featured_media_url":"https:\/\/earthjay.com\/wp-content\/uploads\/2016\/01\/20160125_gibraltar_interpretation_thumb-scaled.jpg","_links":{"self":[{"href":"https:\/\/earthjay.com\/index.php?rest_route=\/wp\/v2\/posts\/3633"}],"collection":[{"href":"https:\/\/earthjay.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/earthjay.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/earthjay.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/earthjay.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3633"}],"version-history":[{"count":0,"href":"https:\/\/earthjay.com\/index.php?rest_route=\/wp\/v2\/posts\/3633\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/earthjay.com\/index.php?rest_route=\/wp\/v2\/media\/3634"}],"wp:attachment":[{"href":"https:\/\/earthjay.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3633"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/earthjay.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3633"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/earthjay.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}