{"id":2375,"date":"2020-05-25T11:07:44","date_gmt":"2020-05-25T11:07:44","guid":{"rendered":"http:\/\/www.icterra.pt\/?p=2375"},"modified":"2020-05-25T11:13:51","modified_gmt":"2020-05-25T11:13:51","slug":"characterization-of-an-intraplate-seismogenic-zone-using-geophysical-and-borehole-data-the-vila-franca-de-xira-fault-portugal","status":"publish","type":"post","link":"https:\/\/www.icterra.pt\/legacy\/index.php\/2020\/05\/25\/characterization-of-an-intraplate-seismogenic-zone-using-geophysical-and-borehole-data-the-vila-franca-de-xira-fault-portugal\/","title":{"rendered":"Characterization of an Intraplate Seismogenic Zone Using Geophysical and Borehole Data: The Vila Franca de Xira Fault, Portugal"},"content":{"rendered":"<div class=\"al-author-name\" style=\"text-align: justify;\"><span style=\"font-family: arial, helvetica, sans-serif;\"><span class=\"al-author-delim\">Jo\u00e3o Carvalho; Daniela Alves<\/span><span class=\"al-author-delim\">; Jo\u00e3o Cabral<\/span><span class=\"al-author-delim\">; Ranajit Ghose<\/span><span class=\"al-author-delim\">; Jos\u00e9 Borges<\/span><span class=\"al-author-delim\">; Ruben Dias<\/span><span class=\"al-author-delim\">; Elsa Ramalho<\/span><span class=\"al-author-delim\">; Bento Caldeira<\/span><span class=\"al-author-delim\">; Jo\u00e3o Casac\u00e3o<\/span><span class=\"al-author-delim\">; Jaime Leote<\/span><\/span><\/div>\n<div><\/div>\n<p>&nbsp;<\/p>\n<div style=\"text-align: justify;\"><span style=\"font-family: arial, helvetica, sans-serif;\">The Vila Franca de Xira (VFX) fault is a regional fault zone located about 25\u00a0km northeast of Lisbon, affecting Neogene sediments. Recent shear\u2010wave seismic studies show that this complex fault zone is buried beneath Holocene sediments and is deforming the alluvial cover, in agreement with a previous work that proposes the fault as the source of the 1531 Lower Tagus Valley earthquake. In this work, we corroborate these results using <em>S<\/em>\u2010wave, <em>P<\/em>\u2010wave, geoelectric, ground\u2010penetrating radar and borehole data, confirming that the sediments deformed by several fault branches are of Upper Pleistocene to Holocene. Accumulated fault vertical offsets of about 3\u00a0m are estimated from the integrated interpretation of geophysical and borehole data, including 2D elastic seismic modeling, with an estimated resolution of about 0.5\u00a0m. The deformations affecting the Tagus alluvial sediments probably resulted from surface or near\u2010surface rupture of the VFX fault during <span class=\"inline-formula no-formula-id\"><span id=\"MathJax-Element-1-Frame\" class=\"MathJax\" tabindex=\"0\" role=\"presentation\" data-mathml=\"&lt;math xmlns=&quot;http:\/\/www.w3.org\/1998\/Math\/MathML&quot;&gt;&lt;mi xmlns=&quot;&quot; mathvariant=&quot;bold&quot;&gt;M&lt;\/mi&gt;&lt;mo xmlns=&quot;&quot;&gt;&amp;#x223C;&lt;\/mo&gt;&lt;mn xmlns=&quot;&quot;&gt;7&lt;\/mn&gt;&lt;\/math&gt;\"><span id=\"MathJax-Span-1\" class=\"math\"><span id=\"MathJax-Span-2\" class=\"mrow\"><span id=\"MathJax-Span-3\" class=\"mi\">M<\/span><span id=\"MathJax-Span-4\" class=\"mo\">\u223c<\/span><span id=\"MathJax-Span-5\" class=\"mn\">7<\/span><\/span><\/span><\/span><\/span> earthquakes, reinforcing the fault as the seismogenic source of regional historical events, as in 1531, and highlighting the need for preparedness for the next event.<\/span><\/div>\n<div style=\"text-align: justify;\"><span style=\"font-family: arial, helvetica, sans-serif;\">Read the full article <a href=\"https:\/\/doi.org\/10.1785\/0220190317\">here<\/a>.<\/span><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Jo\u00e3o Carvalho; Daniela Alves; Jo\u00e3o Cabral; Ranajit Ghose; Jos\u00e9 Borges; Ruben Dias; Elsa Ramalho; Bento Caldeira; Jo\u00e3o Casac\u00e3o; Jaime Leote &nbsp; The Vila Franca de Xira (VFX) fault is a regional fault zone located about 25\u00a0km northeast of Lisbon, affecting Neogene sediments. Recent shear\u2010wave seismic studies show that this complex fault zone is buried beneath [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"_links":{"self":[{"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/posts\/2375"}],"collection":[{"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/comments?post=2375"}],"version-history":[{"count":7,"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/posts\/2375\/revisions"}],"predecessor-version":[{"id":2382,"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/posts\/2375\/revisions\/2382"}],"wp:attachment":[{"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/media?parent=2375"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/categories?post=2375"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.icterra.pt\/legacy\/index.php\/wp-json\/wp\/v2\/tags?post=2375"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}