Study of the evolution of the seismic cycle of stress and strain associated to the El Salvador Fault Zone

• Central America: – Regional studies in Central America (Seismic Hazard). – El Salvador Fault Zone (ESFZ). – Aguacaliente‐Navarro Fault Zone (ANFZ), Central Valley of Costa Rica. – Haiti (seismic hazard) • Spain: – Regional‐Nacional studies of seismic hazards (applications to building codes, eurocode, emergency plans, etc.) – Betic range zone, south of Spain. – Ibero‐Maghrebi region (collision zone

Hacia un modelado preciso de la zona de falla de El Salvador utilizando técnicas geodésicas

[EN] The El Salvador Fault Zone (ESFZ) comprises a set of a strike-slip faults, extending through the Central American Volcanic Arc within El Salvador, where the Cocos plate subducts under the Caribbean plate. These structures act as a boundary between the forearc sliver and the western margin of the Chortís block, accommodating the relative movement between them. The ESFZ has been responsible for several shallow, destructive earthquakes in El Salvador, thus posing a serious threat for millions of inhabitants. Understanding its seismic potential and the behaviour of its different segments results of great importance for the assessment and mitigation of seismic risk in the region. Geodetic techniques, such as GNSS and InSAR, are useful tools for measuring surface deformation related to tectonic activity. We are in the process of updating and densifying the existing GNSS velocity field in El Salvador, aiming to characterise the individual faults in the region by determining their slip rates and locking depth. Additionally, we will process InSAR data, trying to obtain a continuous measurement of the interseismic deformation. The combination of this information with other data (e.g. seismological and geological) through kinematic models will allow us to better understand the factors controlling the seismogenic behaviour of the ESFZ faults, evaluate their seismic potential and improve the seismic hazard assessment.[ES] La Zona de Falla de El Salvador (ESFZ) comprende un conjunto de fallas de deslizamiento extendiéndose a través del Arco Volcánico Centroamericano en El Salvador, donde la placa del Coco subduce bajo la placa Caribe. Estas estructuras actúan como límite entre el antearco volcánico y el margen occidental del bloque Chortís, acomodando el movimiento relativo entre ambos. La ESFZ ha sido responsable de varios terremotos someros destructivos en El Salvador, lo que representa una seria amenaza para millones de habitantes. Comprender su potencial sísmico y el comportamiento de sus diferentes segmentos resulta de gran importancia para la evaluación y mitigación del riesgo sísmico en la región. Las técnicas geodésicas, como GNSS e InSAR, son herramientas útiles para medir la deformación de la superficie relacionada con la actividad tectónica. Actualmente estamos actualizando y densificando el campo de velocidad GNSS existente en El Salvador, con el objetivo de caracterizar las fallas individuales en la región, determinando sus tasas de deslizamiento y profundidad de bloqueo. Además, procesaremos datos InSAR, tratando de obtener una medición continua de la deformación intersísmica. La combinación de esta información con otros datos (por ejemplo, sismológicos y geológicos) a través de modelos cinemáticos nos permitirá comprender mejor los factores que controlan el comportamiento sismogénico de las fallas de ESFZ, evaluar su potencial sísmico y mejorar la evaluación de la amenaza sísmica.This work was supported by the Spanish Ministerio de Universidades (through the Formación del Profesorado Universitario program) under Grant FPU19/03929; and the Spanish Ministerio de Ciencia e Innovación under Grant CGL2017-83931-C3-3-P (GeoActiva project). We thank the Salvadoran Ministerio de Medio Ambiente y Recursos Naturales, especially Douglas Hernández, for providing data for this project. We would also like to thank José Antonio Álvarez-Gómez, from the Universidad Complutense de Madrid, for his help with the seismic analysis and tectonic interpretation. We are grateful to the anonymous reviewers, who helped to improve the original article.Portela-Fernandez, J.; Staller, A.; Bejar-Pizarro, M. (2021). Towards a precise modelling of the El Salvador fault zone using geodetic techniques. En Proceedings 3rd Congress in Geomatics Engineering. Editorial Universitat Politècnica de València. 61-67. https://doi.org/10.4995/CiGeo2021.2021.12711OCS616

Moldels for reproducing the damage scenario of the Lorca earthquake

A damage scenario modelling is developed and compared with the damage distribution observed after the 2011 Lorca earthquake. The strong ground motion models considered include five modern ground motion prediction equations (GMPEs) amply used worldwide. Capacity and fragility curves from the Risk-UE project are utilized to model building vulnerability and expected damage. Damage estimates resulting from different combinations of GMPE and capacity/fragility curves are compared with the actual damage scenario, establishing the combination that best explains the observed damage distribution. In addition, some recommendations are proposed, including correction factors in fragility curves in order to reproduce in a better way the observed damage in masonry and reinforce concrete buildings. The lessons learned would contribute to improve the simulation of expected damages due to future earthquakes in Lorca or other regions in Spain with similar characteristics regarding attenuation and vulnerability

Multi-parametric monitoring of the Alhama de Murcia Fault

La obtención de datos en tiempo real relacionados con la evolución en el espacio y en el tiempo de parámetros geológicos, geofísicos y geoquímicos en la cercanía de fallas activas constituye una oportunidad única de observar todas las partes del ciclo sísmico de una falla y es crucial para avanzar en el entendimiento de su comportamiento a corto y medio plazo. En todo el mundo se están desarrollando cada vez más Near Fault Observatories (NFO) que permitirán la implementación y el desarrollo de metodologías para el seguimiento de la evolución en tiempo real de las fases pre-, sin- y post-sísmicas de una falla activa. En este trabajo se presenta la estrategia de monitorización multi-paramétrica (datos sísmicos, geofísicos, geodésicos, geoquímicos, etc…) diseñada para la falla de Alhama de Murcia (Cordillera Bética Oriental) en el marco del proyecto “InterGeoSima” que pretende ser la semilla para el desarrollo de un futuro NFO adaptado a las especificidades de una falla activa lenta, y que además permita seguir extrayendo datos geológicos, estructurales y geomorfológicos para avanzar en el conocimiento de esta fuente sísmica.Real-time data related to the spatial and temporal evolution of geological, geophysical and geochemical parameters in the vicinity of active faults is a unique opportunity to observe the and quantify the seismic cycle of faults and it is crucial to improve the understanding of seismic behavior in the short and medium term. The number of Near Fault Observatories (NFO) is increasing in Europe and they will enable the scientific community the implementation and development of methodologies for the real-time monitoring of pre-, syn- and post-seismic phases of active faults. In this paper we present the strategy of multi-parametric monitoring (seismic, geophysical, geodetic, geochemical data) designed for the Alhama de Murcia Fault (Betic Cordillera) within the "INTERGEOSIMA" research project, with the aim to be the seed for the development of a future NFO adapted to the specificities of an slow active fault. This strategy will also encourage the acquisition of new, structural and geomorphological data to improve the knowledge about this seismic source.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Economía y Competitividad (MINECO)pu

Main crustal seismic sources in El Salvador

We present a map and a data set containing information about intra-plate seismic sources in El Salvador. These are the results of the field campaigns and data analysis carried out by the research group of Planetary Geodinamics, Active Tectonics and Related Risks from Complutense University of Madrid during the last 12 years. We include two maps, the first map contains 1405 fault traces with evidences of Quaternary activity derived form morphometric, paleoseismological and geomorphological analysis together with field data mapping carried in El Salvador. The second map is a synthesis of the 29 intra-plate seismic sources selected from the quaternary faults map. The geometry of these sources was simplified and we also include a table where some available data of the proposed sources are included, such as their name, orientation, length and slip-rate. For further interpretation and discussion of these sources see (Alonso-Henar et al., 2018) [1, doi.org/10.1016/j.enggeo.2018.06.015]This research was supported by the project“ QUAKESTEP”(CGL2017–83931-C3-1-P) founded by the Spanish Ministry of Science, Innovation and Universities. We are grateful to our colleagues atDGOA-MARN (Observatorio Ambiental del Ministerio de Medio Ambiente y Recursos Naturales de ElSalvador): Manuel Díaz, Walter Hernandez and Douglas Hernández for their assistance. Figures were produced using GMT softwar

Structural evolution of the El Salvador Fault Zone: an evolving fault system within a volcanic arc.

The El Salvador Fault Zone, firstly identifiedafter the 13th February 2001 Mw 6.6 El Salvador earthquake, is a 150 km long,20 km wide right-lateral strike-slip fault system. Ruptures along the ESFZ arethought to be responsible for most of the historical destructive earthquakesalong the El Salvador Volcanic Arc, as well as for most of the currentseismicity of the area. In this work, we focus on the geological setting of thefault zone by describing its geomorphology and structure, using field-based observations,digital terrain modelling, and aerial photograph interpretation with the aim atcontributing to the understanding of the ESFZ slip behaviour. In particular, weaddress the ESFZ structure, kinematics and evolution with time. The ESFZ is a complex set of traces divided inmajor rupture segments characterized by different geometry, kinematics andgeomorphic expressions. Natural fault exposures and paleoseismic trenchesexcavated along the fault show that the strike slip deformation is distributedin several planes. Both geometry and kinematics of the fault zone areconsistent with a transtensional strain regime.The estimated geological slip-rate for the mainfault segments by paleoseismic trenches and displaced geomorphic features impliesa deficit in velocity of the fault compared to the available GPS velocitiesdata. The high vertical scarps of some fault segments would require quaternaryslip rates not coherent neither with measured GPS velocities nor with sliprates obtained from paleoseismic analysis. This mismatch suggests apre-existing graben structure that would be inherited from the previousregional roll back related extensional stage. We consider that the ESFZ isusing this relict structure to grow up along it. As a result, we propose amodel for ESFZ development consistent with all these observations.La Zona de Falla de El Salvador (ZFES) es un sistema de falla de desgarre dextral de 150 km de longitud y 20 de anchura, que fue identificada por primera vez después del terremoto de Mw 6.6 de El Salvador de febrero de 2001. La mayoría de la sismicidad y de los terremotos históricos destructivos producidos en el arco volcánico salvadoreño han sido producidos por la ruptura de la ZFES. Este trabajo se centra en el marco geológico de la zona de falla describiendo su geomorfología y su estructura a través de observaciones de campo, del estudio de los modelos digitales del terreno y de la interpretación de las fotografías aéreas, con el objetivo de avanzar en el conocimiento del comportamiento de la ZFES. En concreto trataremos del estudio de la estructura, la cinemática y la evolución de la ZFES. La ZFES es un complejo sistema de fallas divididas en varios segmentos que se diferencian en la geometría, la cinemática y la expresión geomorfológica. En los afloramientos de la falla, así como en las trincheras paleosismicas excavadas se ha observado que la deformación de desgarre está distribuida en varios planos y tanto la geometría como la cinemática de la zona de falla indican que la ZFES está bajo un régimen de deformación transtensional. La tasa de deformación estimada para los principales segmentos a través del estudio paleosísmico y del análisis de indicadores geomorfológicos desplazados nos muestra un déficit de velocidad para la falla si lo comparamos con los datos obtenidos por GPS. Estos datos tampoco ayudan a explicar la existencia de grandes escarpes verticales que se observan en algunos segmentos de la falla, y que requerirían tasas de deformación muy elevadas. Esta discrepancia sugiere la existencia de una estructura de graben preexistente que puedo ser producida por el “roll-back” de la placa y que creó una fase extensional en el arco volcánico. En este trabajo consideramos que la ZFES está actualmente desarrollándose sobre la estructura extensional relicta y como resultado proponemos un modelo estructural consistente con estas observaciones

Introduced Fruit Species as Food Heritage in the Quebrada de Humahuaca, Jujuy Province, Argentina

European conquerors introduced peaches (Prunus persica) into northwestern Argentina early in the colonial period. Among communities in the Quebrada de Humahuaca peaches represent an important crop and food. This contribution explores whether peaches may be considered food heritage in this part of the Andes. The perception that this exotic species is perceived as heritage is founded in the traditional strategies of management in selecting for certain characteristics that have cultural associations and certain characteristics that dramatically reduced peach diversity at a regional scale. Thus, culture, crop, and environment are interlaced to form—at present—a set of 9 ethno-varieties with typical features and defined uses. People selected peaches with regard to preferences of consumption, and in recent times their importance to commercialization. Peaches, as in the case of different Andean crops, such as potatoes and corn, are important to local consumption and ethnic identity resulting in networks of exchange—fairs and markets—enabling these communities to share in the fruits of their ethnic communities. Heritage is characterized as the capacity to symbolically represent the identity of a community, through phenotypic distinctions of the local variety of peaches or “duraznos de la Quebrada” (peaches from the Quebrada).Facultad de Ciencias Naturales y Muse

ANÁLISIS DE LA SERIE TEMPORAL DE LA ESTACIÓN DE MONITOREO CONTINUO CUEC - REGME

En el  presente estudio se realiza un análisis exhaustivo de la serie temporal de la estación de monitoreo contínuo CUEC en el periodo 2008-2014. Para tal efecto se obtuvieron soluciones diarias de coordenadas con sus respectivas precisiones en cada una de sus componentes tanto horizontales como verticales, para posteriormente realizar un análisis riguroso de la serie mediante una descomposición aditiva determinando la estacionalidad o periodicidad, la tendencia y el tipo de ruido presente en la serie. Previo a la descomposición se realizó una limpieza o depuración de los datos mediante la detección y corrección de saltos en la serie y eliminación de valores atípicos. Para la determinación de la tendencia utilizamos una regresión lineal ponderada cuya solución se obtuvo mediante un ajuste mínimo cuadrático, en la determinación de la estacionalidad se realizó un análisis espectral de la serie en el dominio de las frecuencias, ya que esta es una medidad que sirve para representar los ciclos, y en cuanto a la  obtención del ruido se lo realizó mediante el estudio del espectro de potencia. Los resultados obtenidos muestran que la estación CUEC tiene una periodicidad anual (1.03 años) en todas sus componentes y un tipo de ruido gaussiano fraccionario con un índice espectral entre 0 y -1, considerando que estos valores no reflejan el verdadero tipo de ruido existente, debido principalmente a un alto porcentaje de datos perdidos

Improving multi-technique monitoring using Sentinel-1 and Cosmo-SkyMed data and upgrading groundwater model capabilities

Aquifer-systems have become a strategic source of fresh water in the present climatic conditions, especially under stress in arid regions like the Iberian Mediterranean Arc. Understanding the behavior of groundwater reservoirs is crucial to their well-management and mitigation of adverse consequences of overexploitation. In this work, we use space geodetic measurements from satellite interferometric synthetic aperture radar (InSAR) and Global Positioning System (GPS) data, covering the period 2011–2017, to predict and validate the ground surface displacement over the fastest subsiding basin due to groundwater withdrawal in Europe (>10 cm/year). The 2D decomposition of InSAR displacements from Cosmo-SkyMed and Sentinel-1 satellites allows us to detect horizontal deformation towards the basin center, with a maximum displacement of 1.5 cm/year. InSAR results were introduced in a newly developed methodology for aquifer system management to estimate unknown pumping rates for the 2012–2017 period. This study illustrates how the combination of InSAR data, groundwater flow and deformation models can be used to improve the aquifer-systems sustainable management.This work was supported by the Spanish Ministry of Science, Innovation and Universities (MICINN), Spain; the State Agency of Research (AEI), Spain; and European Funds for Regional Development (FEDER), under projects AQUARISK (ESP2013-47780-C2-2-R), TEMUSA (TEC2017-85244-C2-1-P) and STAR-EO (TIN2014-55413-C2-2-P). First author shows gratitude for PhD student contract BES-2014-069076. A first version of this work was written during the research stay of first and second authors in the Università degli Studi di Firenze supported by the Spanish Ministry of Education, Culture and Sport, under fellowships EEBB-I-18-13014 and PRX17/00439, respectively