<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0016-7169</journal-id>
<journal-title><![CDATA[Geofísica internacional]]></journal-title>
<abbrev-journal-title><![CDATA[Geofís. Intl]]></abbrev-journal-title>
<issn>0016-7169</issn>
<publisher>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México, Instituto de Geofísica]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0016-71692017000200219</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Interior Imaging of El Castillo Pyramid, Chichen Itza, Mexico, Using ERT-3D Methods: Preliminary Results]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Chavez]]></surname>
<given-names><![CDATA[René E.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Tejero]]></surname>
<given-names><![CDATA[Andrés]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Argote]]></surname>
<given-names><![CDATA[Denisse L.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cifuentes]]></surname>
<given-names><![CDATA[Gerardo]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Hernández-Quintero]]></surname>
<given-names><![CDATA[Juan Esteban]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[García-Serrano]]></surname>
<given-names><![CDATA[Alejandro]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad Nacional Autónoma de México Instituto de Geofísica ]]></institution>
<addr-line><![CDATA[ CDMX]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="A02">
<institution><![CDATA[,Universidad Nacional Autónoma de México Facultad de Ingeniería ]]></institution>
<addr-line><![CDATA[ CDMX]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="A03">
<institution><![CDATA[,INAH  ]]></institution>
<addr-line><![CDATA[ CDMX]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>06</month>
<year>2017</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>06</month>
<year>2017</year>
</pub-date>
<volume>56</volume>
<numero>2</numero>
<fpage>219</fpage>
<lpage>227</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0016-71692017000200219&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0016-71692017000200219&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0016-71692017000200219&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract: The famous El Castillo pyramid, located in Chichen Itza, towards the northern portion of the Yucatan Peninsula, Mexico, is an emblematic structure of this archaeological site and recognized as one of the man-made world seven wonders. The archaeologists that restored this structure during the 1930&#8217;s discovered a smaller pyramid inside this preHispanic edifice, which corresponded to an older Mayan period. The possibility of finding other construction periods inside this edifice should be important in order to reconstruct the Mayan history of the region. Previous geophysical studies carried out in 2014 by the authors, showed a buried natural cavity partially filled with water beneath El Castillo pyramid, using novel Electrical Resistivity Tomography (ERT) arrays. Employing a similar technique, a series of flat electrodes were deployed on each of the 9 bodies (or levels) conforming the pyramid plus the base of the structure, keeping a constant distance between each electrode. A precise topographic control for each electrode was fulfilled and introduced in the inversion process. 37,520 observations inside the pyramid were computed. So far, five of the 10 observation levels (19,400 points), were processed. Horizontal and vertical slices of this inverted image were analyzed. Examining the differences in the resistivity values and their gradients, allowed to locate the first substructure (explored in the 1930&#8217;s), as well as to infer a second substructure inside the previous one. An ERT-2D profile was surveyed inside El Castillo pyramid at the interior of a tunnel excavated in 1934 and the stairway of the first inner pyramid. Results from this study seem to confirm the evidence of a second substructure within El Castillo&#8217;s interior. Such feature possesses a probable intact chamber (a rectangular room 3 m high) on its upper part and inferred dimensions of 10 m high and 23 m per side at its base, assuming that the end of this profile lies on the middle of substructure 2. When the inversion will be carried out for the 10 levels, a better resolution will be reached for the upper portions of the resistivity model.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen: La famosa Pirámide del Castillo, ubicada en Chichén Itzá, hacia la parte norte de la Península de Yucatán, México, es una estructura emblemática de este sitio arqueológico y elegida como una de las siete maravillas hechas por el hombre. Los arqueólogos que restauraron esta estructura durante los años 30 descubrieron una pirámide más pequeña dentro de este edificio prehispánico, que correspondía a un período maya más antiguo. La posibilidad de encontrar otros períodos de construcción dentro de este edificio es muy importante para reconstruir la historia maya de la región. Estudios geofísicos anteriores llevados a cabo por los autores en 2014, utilizando nuevos arreglos de Tomografía de Resistividad Eléctrica (TRE), mostraron una cavidad natural parcialmente llena de agua dulce debajo de la Pirámide de El Castillo. Empleando una técnica similar, se desplegó una serie de electrodos planos en cada uno de los 9 cuerpos (o niveles) que conformaban la pirámide más la base de la estructura, manteniendo constante la distancia entre cada electrodo. Se realizó un control topográfico preciso para cada electrodo, el que se introdujo en el proceso de inversión. Se calcularon 37.520 observaciones dentro de la pirámide. Cinco de los 10 niveles de observación (19.400 puntos), han sido procesados hasta ahora. Se analizaron secciones horizontales y verticales de esta imagen invertida. Examinando las diferencias en los valores de resistividad y sus correspondientes gradientes se pudieron localizar, la primera subestructura (explorada en la década de 1930), así como inferir una segunda subestructura dentro de la anterior. Se levantó un perfil ERT-2D dentro de la pirámide de El Castillo, al interior de un túnel excavado en 1934 y la escalera de la primera pirámide interna. Los resultados de este estudio parecen confirmar la evidencia de una segunda subestructura dentro del interior de El Castillo. Dicho rasgo resistivo posee una cámara probablemente intacta (una habitación rectangular de 3 m de altura) en su parte superior y dimensiones inferidas de 10 m de altura y 23 m por lado en su base, suponiendo que el final de este perfil se encuentre en el centro de la subestructura 2. Cuando la inversión se lleve a cabo integrando los 10 niveles, se tendrá una mejor resolución para las porciones superiores del modelo de resistividad.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Tomografía de resistividad eléctrica]]></kwd>
<kwd lng="es"><![CDATA[proceso de inversión]]></kwd>
<kwd lng="es"><![CDATA[pirámide El Castillo]]></kwd>
<kwd lng="es"><![CDATA[Chichen Itza]]></kwd>
<kwd lng="es"><![CDATA[México]]></kwd>
<kwd lng="es"><![CDATA[Arqueología]]></kwd>
<kwd lng="en"><![CDATA[Electrical Resistivity Tomography]]></kwd>
<kwd lng="en"><![CDATA[inversion process]]></kwd>
<kwd lng="en"><![CDATA[El Castillo pyramid]]></kwd>
<kwd lng="en"><![CDATA[Chichen Itza]]></kwd>
<kwd lng="en"><![CDATA[Mexico]]></kwd>
<kwd lng="en"><![CDATA[archaeology]]></kwd>
</kwd-group>
</article-meta>
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