Conferencias

URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/18051

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Mostrando 1 - 11 de 11

Arsenic in wells at the Guayabo Caldera in Northwest Costa Rica
(International Association of Volcanology and Chemistry of the Earth's Interior, 2018-09) Martínez Cruz, María; Brenes-Navarro, Gilberto; Herrera-Murillo, Jorge
The Guayabo Caldera, a 14 km diameter volcanic depression with Miravalles volcano rising 2028 ma.s.l. in the norte astern side of so called, formed by repeated eruption sand multiple collapses which dis membered earlier volcanoes between 1.5 to 0.6 m.y.ago. The pyroclastic-flow sheets represent more than 30 km 3 of dacitict or hyolitic magma associated to crystal fractionation processes.
Aspectos espeleogenéticos, hidrogeológicos y de geomorfología kárstica de Venado de San Carlos
(Universidad de Costa Rica, 2019) Ulloa, Andrés; Argüello, Alejandro; Vargas, Mariángela; Obando, Adrián; Martínez Cruz, María
En los últimos años, personal de la UCR con colaboración de espeleólogos y la administración de Cavernas de Venado, realizó la cartografía de aproximadamente 5 kilómetros de pasajes de cuevas. Esta cartografía ha permitido adquirir un entendimiento integral de las condiciones geológicas, estructurales, hidrogeológicas y espeleogenéticas del sistema kárstico. El karst de la zona de Venado de San Carlos, se desarrolla en las calizas de la formación Venado (Mioceno Medio a Superior), la cual se encuentra cubierta parcialmente por depósitos volcanogénicos (e.g. lavas, lahares, tefras) del Plio-Pleistoceno. La cobertura volcánica ha limitado el desarrollo de lapiaz. Las geomorfologías kársticas superficiales más sobresalientes son las dolinas, sumideros y surgencias kársticas. Las dolinas generalmente son de subsidencia y pequeñas (<20 m de diámetro). A partir de la cartografía de cuevas, se determinó 2 tipos de patrones: 1) rectilíneo (e.g., cueva Menonitas), que se encuentra asociado a alineamientos estructurales; y 2) entrelazado (algunos sectores de la cueva Gabinarraca), que podrían haberse formado durante inundaciones en la cueva, las cuales propician la disolución de pasajes secundarios. La cobertura volcánica aporta gran cantidad de sedimentos a la cueva, lo cual ha ocasionado obstrucciones temporales de algunos pasajes y generado evidencias de disolución del techo de la cueva (paragénesis). Actualmente se trabaja en la caracterización hidrogeológica del acuífero kárstico, realizando mediciones de caudales y ensayos con diversos trazadores para corroborar la conectividad hidrogeológica a través de los pasajes estrechos, donde no ha sido posible continuar las exploraciones espeleológicas. Asimismo, se reconocieron evidencias neotectónicas en algunas trazas de fallas que intersecan el sistema de cuevas.
Co-Designing Communication & Hazard Preparedness Strategies: Turrialba volcano, Costa Rica
(Europan Geociences Union, 2014) Van Manen, Saskia; Avard, Geoffroy; Martínez Cruz, María
Coda wave attenuation in Mara Rosa seismic zone
(Sociedade Brasileira de Geofísica, 2013-08-26) schmidt, kellin; Ferreira, Vinicius; Vieira Barros, Lucas; Quintero, Ronnie
Small local earthquakes from aftershock sequence in Mara Rosa, Goiás state, Brazil were used to estimate the coda wave attenuation in the frequency band of 1 to 20 Hz. The time-domain coda-decay method of a single backscattering model is employed to estimate frequency dependence of quality factor (Qc) of coda waves modeled using Qc = Q0fη, Q0 is the coda quality factor at a frequency of 1 Hz and η is the frequency parameter. Qc values have been computed at central frequencies and (band) of 1.5 (1-2), 3.0 (2-4), 6.0 (4-8), 9.0 (6-12), 12 (8-16) and 18 (12-24) Hz in the lapse time ranging from 5 to 25 sec in step of 5 seconds. It was determined the functional form Qc = (10.78) f(1.84)) .
Gas emissions from the Hyper-Acid Crater Lake of Poás Volcano, Costa Rica
(The International Union of Geodesy and Geophysics (IUGG), 2015-06) de Moor, Joost Maarten; Avard, Geoffroy; AIUPPA, Alessandro; Liuzzo, Giudice; Fischer; Martínez Cruz, María; Pacheco Alvarado, Javier
Resumen de la presentación sobre las emisiones de gases del lago del cráter hiperácido del volcán Poás, Costa Rica en la 26th IUGG General Assembly
Geochemistry and fluid circulation at the Tenorio volcanic complex (Costa Rica)
(Geoitalia, 2013-09) Vaselli, Orlando; Tassi, Franco; Giolito, C.; Martínez Cruz, María; Fernández soto, Erick; Duarte, Eliecer; Barquero, J.; Capaccioni, Bruno; Van Bergen, M. J.
The present work reports the geochemical results gathered from thermal and cold water and discharges, mainly located in the eastern part of the volcanic area of Tenorio
Magmatic volatiles in ash leachates and environmental impact assessment of the 29-30 October 2014 eruption of Turrialba volcano
(The International Union of Geodesy and Geophysics (IUGG), 2015-06) Martínez Cruz, María; de Moor, Joost Maarten; Avard, Geoffroy; Keizer, M.; Berrocal, Milena; Osorno, D.; Herrera, Jorge
Resumen de presentación sobre volátiles magmáticos en lixiviados de cenizas y evaluación de impacto ambiental de la erupción del volcán Turrialba del 29 al 30 de octubre de 2014 en la 26th IUGG General Assembly
Magmatic volatiles in ash leachates and environmental impact assessment of the 29-30 October 2014 phreatic eruptions of Turrialba Volcano, Costa Rica
(The International Union of Geodesy and Geophysics (IUGG), 2015) Martínez Cruz, María; de Moor, Joost Maarten; Di Piazza, Andrea; Keizer, M.; Berrocal, Milena; Avard, Geoffroy; Rizzo, Andrea Luca; Osorno, D.; Herrera., Jorge; Carapezza, Maria Luisa
OKSP: a novel deep learning automatic event detection pipeline for seismic monitoring in Costa Rica
(Instituto de Ingenieros Eléctricos y Electrónicos (IEEE), 2021) Van der Laat, Leonardo; Baldares, Ronald; Chaves, Esteban; Meneses, Esteban
Small magnitude earthquakes are the most abundant but the most difficult to locate robustly and well due to their low amplitudes and high frequencies usually obscured by heterogeneous noise sources. They highlight crucial information about the stress state and the spatio-temporal behavior of fault systems during the earthquake cycle, therefore, its full characterization is then crucial for improving earthquake hazard assessment. Modern deep learning algorithms along with the increasing computational power and efficiency are exploiting the continuously growing seismological databases, worldwide, allowing scientists to improve the completeness for earthquake catalogs, systematically detecting and locating smaller magnitude earthquakes and reducing the errors introduced mainly by human intervention through traditional approaches in seismological observatories. In this work, we introduce OKSP, a novel deep learning automatic earthquake detection pipeline for seismic monitoring in Costa Rica. Using Kabre supercomputer from the Costa Rica High Technology Center, we applied OKSP to the day before and the first 5 days following the Puerto Armuelles, M6.5, earthquake that occurred on 26 June, 2019, along the Costa Rica-Panama border and found 1100 more earthquakes previously unidentified by the Volcanological and Seismological Observatory of Costa Rica. From these events, a total of 23 earthquakes with magnitudes below 1.0 occurred a day to hours prior to the mainshock, shedding light about the rupture initiation and earthquake interaction leading to the occurrence of this productive seismic sequence. Our observations show that for the study period, the model was 100% exhaustive and 82% precise, resulting in an F1 score of 0.90. This effort represents the very first attempt for automatically detecting earthquakes in Costa Rica using deep learning methods and demonstrates that, in the near future, earthquake monitoring routines will be carried out entirely by AI algorithms.
Parâmetros de fonte de sismos locais por inversão de formas de ondas
(Sociedade Brasileira de Geofísica, 2010-11) Zahradnik, Jiri; Vieira Barros, Lucas; Quintero, Ronnie
The main purpose of this work is to invert seismic waveforms in order to obtain moment tensor for two medium size earthquakes detected by OVSICORI-UNA Costa Rica permanent seismic network, occurred in 2004, following the mainshock of November 20 at 08:07 UTC (Mw=6.4 GCMT). The inversion for the focal mechanism is made using the package ISOLA (Zahradnik et al., 2005, Sokos & Zahradnik, 2008) and the seismicity are associated with a fault system that delineates the upper plate between the Caribbean plate and Panama Block. The obtained focal mechanisms are in agreement with results obtained by Pacheco et al. (2006) for this seismicity.
Seismogenic zone structure along the middle America trench: results from the Costa Rica seismogenic zone experiment
(IUGG General Assembly, 2003-06-30) Deshon, Heather R.; Schwartz, Susan Y.; Bilek, Susan; Newman, Andrew V.; Dorman, LeRoy; Protti, Marino
Summary of the paper Seismogenic zone structure along the middle america trench: Results fromthe costa rica seismogenic zone experiment

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