Construction of probabilistic event trees for eruption forecasting at Sinabung volcano, Indonesia 2013-14

Eruptions of Sinabung volcano, Indonesia have been ongoing since 2013. Since that time, the character of eruptions has changed, from phreatic to phreatomagmatic to magmatic explosive eruptions, and from production of a lava dome that collapsed to a subsequent thick lava flow that slowly ceased to be active, and later, to a new lava dome. As the eruption progressed, event trees were constructed to forecast eruptive behavior six times, with forecast windows that ranged from 2. weeks to 1. year: November 7-10, December 12-14, and December 27, 2013; and January 9-10, May 13, and October 7, 2014. These event trees were successful in helping to frame the forecast scenarios, to collate current monitoring information, and to document outstanding questions and unknowns. The highest probability forecasts closely matched outcomes of eruption size (including extrusion of the first dome), production of pyroclastic density currents, and pyroclastic density current runout distances. Events assigned low probabilities also occurred, including total collapse of the lava dome in January 2014 and production of a small blast pyroclastic density current in February 2014

Intrusión magmática asociada a la sismicidad distal en el volcán Sabancaya, 2020 – 2021

El volcán Sabancaya ha registrado entre el 2020 y 2021 una importante sismicidad volcano tectónica distal – VTD, la cual se ha manifestado en algunas ocasiones a modo de enjambres sísmicos. El registro de enjambres sísmicos VTD en ambientes volcánicos se asocia a la sobrepresurización de los acuíferos que cruzan las fallas tectónicas debido a la intrusión de magma, y en el volcán Sabancaya ha sido asociada a intrusiones importantes de magma provenientes de la cámara magmática localizada por debajo del volcán Hualca Hualca. La cual al migrar hacia el volcán muestra incrementos de sismicidad proximal asociada a la dinámica de fluidos y actividad explosiva y el registro de valores importantes de anomalías térmicas, que indicaría un mayor volumen de magma involucrado en el conducto del cráter, que conllevo a la formación domos exógenos y endógenos. La sismicidad desde el 2013 y aquella como parte del proceso eruptivo, sigue el modelo conceptual de 4 etapas de sismicidad de White y McCausland (2019) que precede a las erupciones en volcanes inactivos. Antes sus inicios en 2016, el proceso eruptivo sugiere un sistema más abierto, es por ello, que no ocurren todas las etapas, como es el caso del periodo comprendido entre el 2020 y 2021, en el cual el patrón sísmico muestra el registro de sismos VTDs debido a la intrusión de magma (Etapa 2) seguida por sismicidad proximal asociada a la migración de fluidos y gases hacia la superficie (Etapa 3) y el ascenso final del magma a modo de sismos acoplados (Etapa 4)

Capturing, Preserving, and Digitizing Legacy Seismic Data from the Montserrat Volcano Observatory Analog Seismic Network, July 1995–December 2004

An eruption of the Soufrière Hills Volcano (SHV) on the eastern Caribbean island of Montserrat began on 18 July 1995 and continued until February 2010. Within nine days of the eruption onset, an existing four‐station analog seismic network (ASN) was expanded to 10 sites. Telemetered data from this network were recorded, processed, and archived locally using a system developed by scientists from the U.S. Geological Survey (USGS) Volcano Disaster Assistance Program (VDAP). In October 1996, a digital seismic network (DSN) was deployed with the ability to capture larger amplitude signals across a broader frequency range. These two networks operated in parallel until December 2004, with separate telemetry and acquisition systems (analysis systems were merged in March 2001). Although the DSN provided better quality data for research, the ASN featured superior real‐time monitoring tools and captured valuable data including the only seismic data from the first 15 months of the eruption. These successes of the ASN have been rather overlooked. This article documents the evolution of the ASN, the VDAP system, the original data captured, and the recovery and conversion of more than 230,000 seismic events from legacy SUDS, Hypo71, and Seislog formats into Seisan database with waveform data in miniSEED format. No digital catalog existed for these events, but students at the University of South Florida have classified two‐thirds of the 40,000 events that were captured between July 1995 and October 1996. Locations and magnitudes were recovered for ~10,000 of these events. Real‐time seismic amplitude measurement, seismic spectral amplitude measurement, and tiltmeter data were also captured. The result is that the ASN seismic dataset is now more discoverable, accessible, and reusable, in accordance with FAIR data principles. These efforts could catalyze new research on the 1995–2010 SHV eruption. Furthermore, many observatories have data in these same legacy data formats and might benefit from procedures and codes documented here

New insights into Kawah Ijen’s volcanic system from the wet volcano workshop experiment

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