Observatorio Vulcanológico y Sismológico de Costa Rica

URI permanente para esta comunidadhttp://10.0.96.45:4000/handle/11056/14933

El Observatorio Vulcanológico y Sismológico de Costa Rica (OVSICORI) de la Universidad Nacional, es un instituto de investigación universitaria dedicado a la investigación de los volcanes, los sismos y otros procesos tectónicos, con el propósito de encontrar aplicaciones útiles a la sociedad que ayuden a mitigar los efectos adversos de esos fenómenos al desarrollo económico y social. Se trata de un observatorio, por cuanto una cantidad considerable de su esfuerzo va orientada a documentar la actividad sísmica, volcánica y la deformación cortical que, a su vez, retroalimenta a las actividades investigativas propias de un instituto de investigación universitaria.

Contáctenos:

Página web: www.ovsicori.una.ac.cr

Correo: ovsicori@una.cr

Teléfono: (506) 2562 4001 / (506) 2261 0611 / (506) 2261 0781

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Mostrando 1 - 5 de 5

Aerial strategies advance volcanic gas measurements at inaccessible, strongly degassing volcanoes
(American Association for the Advancement of Science, 2020-10-30) Liu, Emma; Bitetto, Marcello; Clarke, Robert; Edmonds, Marie; Hayer, Catherine; Nowicki, Scott; Schipper, C Ian; Aiuppa, Alessandro; Alan, Alfredo; Arellano, Santiago; Bobrowski, Nicole; Carn, Simon A.; Corrales, Ernesto; Moor, J. Maarten de; Díaz, Jorge Andrés; Fischer, Tobias P.; Freer, Jim E.; Fricke, G. Matthew; Galle, Bo O.; Itikarai, Ima; Jones, J.; Mason, Emily; Mulina, Kila; Rahilly, Kristen E; Rüdiger, Julian; Watson, I. Matthew; Gerdes, Gustav; Giudice, Gaetano; Gutmann, Alexandra; McCormick, Brendan; Richardson, Thomas
Volcanic emissions are a critical pathway in Earth’s carbon cycle. Here, we show that aerial measurements of volcanic gases using unoccupied aerial systems (UAS) transform our ability to measure and monitor plumes remotely and to constrain global volatile fluxes from volcanoes. Combining multi-scale measurements from ground-based remote sensing, long-range aerial sampling, and satellites, we present comprehensive gas fluxes—3760 ± [600, 310] tons day−1 CO2 and 5150 ± [730, 340] tons day−1 SO2—for a strong yet previously uncharac terized volcanic emitter: Manam, Papua New Guinea. The CO2/ST ratio of 1.07 ± 0.06 suggests a modest slab sediment contribution to the sub-arc mantle. We find that aerial strategies reduce uncertainties associated with ground-based remote sensing of SO2 flux and enable near–real-time measurements of plume chemistry and carbon isotope composition. Our data emphasize the need to account for time averaging of temporal variability in volcanic gas emissions in global flux estimates
Aftershocks of the 2012 Mw 7.6 Nicoya, Costa Rica, earthquake and mechanics of the plate interface
(Seismological Society of America (SSA), 2017-05-02) Chaves, Esteban; Duboeuf, Laure; Schwartz, Susan; Lay, Thorne; Kintner, Jonas
Subduction of the Cocos plate beneath the Nicoya Peninsula, Costa Rica, generates large underthrusting earthquakes with a recurrence interval of about 50 yrs. The most recent of these events occurred on 5 September 2012 (Mw 7.6). A vigorous sequence of more than 6400 aftershocks was recorded by a local seismic network within the first four months after the mainshock. We determine locations and focal mechanisms for as many aftershocks as possible with M ≥1:5 occurring within the first nine days of the mainshock, all aftershocks with M ≥3 through the end of 2012, and all events with M ≥4 through the end of 2015. We determine faulting geometries using regional full waveform moment tensor (MT) inversion for the largest events (M ≥4) and P-wave first-motion polarities for smaller events, producing a mechanism catalog with 347 earthquakes. Sixty percent of these events are identified as underthrusting, and their locations are compared with spatial distributions of mainshock slip, afterslip, prior interplate seismicity, and slow-slip phenomena to better understand the mechanical behavior of the plate interface. Most of the aftershocks on the megathrust occur up-dip of the coseismic slip, where afterslip is large, and between coseismic slip and shallow slow-slip patches. The pattern of interplate seismicity during the interseismic period is similar to that for the aftershocks but does not extend to as great a depth. The coseismic slip extends even deeper than the interplate aftershocks, suggesting that the mainshock ruptured a strongly locked patch driving down-dip slip into the conditionally stable part of the deep plate interface that also hosts slow slip. About 80% of the aftershocks have one nodal plane oriented favorably to promote failure from static stress changes following the mainshock and early afterslip, whereas most others occur in regions of large afterslip.
Global quieting of high-frequency seismic noise due to COVID-19 pandemic lockdown measures
(American Association for the Advancement of Science (AAAS), 2020) Lecocq, Thomas; Hicks, Stephen; Van Noten, Koen ; van wijk, kasper; Koelemeijer, Paula; De Plaen, Raphael; Massin, Frédérick; Hillers, Gregor; Anthony, Robert E.; Apoloner, Maria-Theresia; Arroyo-Solórzano, Mario; Assink, Jelle; Büyükakpınar, Pınar; Cannata, Andrea; Cannavo', Flavio; Carrasco, Sebastian; Caudron, Corentin; Chaves, Esteban; Cornwell, David; Craig, David; den Ouden, Olivier; Diaz, Jordi; Donner, Stefanie; Evangelidis, Christos; Evers, Läslo; Fauville, Benoit; Fernandez, Gonzalo; Giannopoulos, Dimitrios; Gibbons, Steven J.; Girona, Társilo; Grecu, Bogdan; Grunberg, Marc; Hetényi, György; Horleston, Anna; Inza, Adolfo; Irving, Jessica C.E.; Jamalreyhani, Mohammadreza; Kafka, Alan; Koymans, Mathijs R.; Labedz, Celeste; Larose, Eric; Lindsey, Nathaniel; McKinnon, Mika; Megies, Tobias; Miller, Meghan; Minarik, William; Moresi, Louis-Noel; Márquez Ramirez, Víctor H; Möllhoff, Martin; Nesbitt, Ian; Niyogi, Shankho; Ojeda, Javier; Oth, Adrien; Proud, Simon; Pulli, Jay; Retailleau, Lise; Rintamäki, Annukka E.; Satriano, Claudio; Savage, Martha; Shani-Kadmiel, Shahar; Sleeman, Reinoud; Sokos, Efthimios; Stammler, Klaus; Stott, Alexander; Subedi, Shiba; Sørensen, Mathilde Bøttger; Taira, Taka'aki; Tapia, Mar; Turhan, Fatih; van der Pluijm, Ben; Vanstone, Mark; Vergne, Jérôme; Vuorinen, Tommi; Warren, Tristram; Wassermann, Joachim; Xiao, Han
Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the coronavirus disease 2019 (COVID-19) pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record. Although the reduction is strongest at surface seismometers in populated areas, this seismic quiescence extends for many kilometers radially and hundreds of meters in depth. This quiet period provides an opportunity to detect subtle signals from subsurface seismic sources that would have been concealed in noisier times and to benchmark sources of anthropogenic noise. A strong correlation between seismic noise and independent measurements of human mobility suggests that seismology provides an absolute, real-time estimate of human activities.
The 27 February 2022 Lop Nor earthquake: detectability, location, and discrimination
(Seismological Society of America (SSA), 2022) Gibbons, Steven J.; Chaves, Esteban; Fisk, Mark
A seismic event with mb 4.8 (Mw 4.2) was detected close to the Chinese Lop Nor nuclear test site on 27 February 2022. Waveforms recorded at regional and far regional distances in central Asia indicate greater likeness with previous earthquakes in the region than with historical nuclear tests. We investigate signal-to-noise ratio (SNR) at regional and global stations, and find the best signals in central Asia and Alaska. Lower SNR at stations in China, Europe, and Australia is likely related to the radiation pattern. A joint probabilistic location of the 2022 event and well-constrained historical nuclear tests indicates an epicenter near 41.88° N and 88.10° E, about 25 km northwest of the tunnel portion of the test site. A moment tensor inversion using high-quality regional signals indicates a nearly deviatoric source with a 72% double couple and a reverse fault mechanism. The centroid depth is 20–25 km, consistent with depth phases recorded in Alaska. The observed faulting geometry and source composition for the 2022 Lop Nor event is consistent with previous earthquakes in the region and the spatial alignment of local geomorphological features, indicating tectonic and not anthropogenic origin.
Volcano Seismology: Detecting Unrest in Wiggly Lines
(Springer Science and Business Media Deutschland GmbH, 2019) Salvage, Rebecca; Karl, Sandra.; Neuberg, Jourgen. W.
Seismology is a useful tool to gain a better understanding of volcanic unrest in real time as it unfolds. The generation of seismic signals in a volcanic environment has been linked to a number of different physical processes occurring at depth, including fracturing of the volcanic edifice (producing high frequency seismicity) and movement of magmatic fluids (producing low frequency seismicity). Further classification of seismic signals according to their waveform similarity, in addition to their frequency content, allows greater detail in temporal and spatial changes of seismicity to be detected. At Soufrière Hills volcano, Montserrat, one of the target volcanoes of the VUELCO project, families of similar waveforms provided valuable insight into evaluating the significance of ongoing unrest. In June 1997 over 6000 more events were able to be identified over a 5 day period of interest (22 to 25 June) by using families of seismic events, rather than a standard amplitude-based detection algorithm. In total, 11 families were identified, with the events clustering into a number of swarms, suggesting a repeating and non destructive cyclic source mechanism. Since each family is believed to represent a distinct source location and mechanism, identifying 11 coexisting families reflects the complex diversity of physical processes which act simultaneous at this volcano. In July 2003, conditions at the volcano had clearly changed since only one family of seismicity was identified. The source location of this family appeared to shift with time from 8 July (when no events from the family were identified) to 12 July (where most events had a cross correlation coefficient over 0.9). In addition, the use of families appears to greatly aid hindsight forecasting attempts for the large scale dome collapses of 1997 and 2003 using the Failure Forecast Method. Knowledge of the temporal and spatial extent of seismicity during periods of unrest, its source mechanism and its relationship to physical processes at depth is essential for decision and policy makers for risk mitigation. However, the source mechanisms of such volcanic seismicity is still much debated and appears to often be misinterpreted because of compromising assumptions used in the numerical modelling of inverting such sources. Use of a spatially extended source such as a ring fault structure, rather than a single point for determining the origin of low frequency seismicity, is now thought to be more realistic for the mechanism of such events since it more accurately represents the movement of magma through a conduit. However, use of this spatially extended source instead of a simple single point results in a large underestimation of slip from P-wave amplitudes, which may lead to an underestimation in magma ascent rates, with large consequences for eruption forecasting. Additionally, the P-wave radiation patterns exhibited by these two mechanisms are remarkably similar, and can only be distinguished if the small radial radiation lobes can be determined. In a volcanic environment this is extremely difficult due to large uncertainties in earthquake source depth locations, and the implementation of small aperture seismic networks

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