TY - JOUR

T1 - Local Earthquake Tomography of the Nevado del Huila Volcanic Complex (Colombia)

T2 - Magmatic and Tectonic Interactions in a Volcanic-Glacier Complex System

AU - García, M. A.

AU - Vargas, C. A.

AU - Koulakov, I. Yu

N1 - Funding Information: experiment, can provide statistically robust anomalies. This fact for the case of our study is supported by the synthetic modeling.

PY - 2019/2/1

Y1 - 2019/2/1

N2 - Nevado del Huila is an active volcano in Colombia having high explosive potential and serious hazard for surrounding population. Here we present the first 3‐D seismic velocity model of the Nevado del Huila Volcanic Complex based on local earthquake tomography. We used 13,790 events with the corresponding 49,412 P wave and 47,972 S wave arrival times recorded by the Volcanological and Seismological Observatory of Popayán (Colombia). The period of observations from 2007 to 2016 covers stages of eruptions (first registered to date) and repose of the volcano. The seismic structure reveals two prominent nearly vertical anomalies with high Vp/Vs ratio that are interpreted as conduits connecting the volcano structures with a deeper seated magma reservoir. The anomaly beneath the southern flank of the volcano is limited by the Calambayú Fault and coincides with the dense seismicity cluster. We interpret this anomaly as the pathway of fluids following the weakened rocks along the fault zone. Another anomaly located beneath the main summit of Nevado del Huila probably represents the magma conduit that fed the previous eruption of this volcano. The seismicity here is not as intensive as that beneath the southern flank, which is possibly caused by higher temperature and ductile properties of rocks in the conduit. At depths from 2 to 4 km below surface, we observe the limit between higher Vp/Vs below and lower Vp/Vs above that possibly represents the level of fluid degassing due to decompression.

AB - Nevado del Huila is an active volcano in Colombia having high explosive potential and serious hazard for surrounding population. Here we present the first 3‐D seismic velocity model of the Nevado del Huila Volcanic Complex based on local earthquake tomography. We used 13,790 events with the corresponding 49,412 P wave and 47,972 S wave arrival times recorded by the Volcanological and Seismological Observatory of Popayán (Colombia). The period of observations from 2007 to 2016 covers stages of eruptions (first registered to date) and repose of the volcano. The seismic structure reveals two prominent nearly vertical anomalies with high Vp/Vs ratio that are interpreted as conduits connecting the volcano structures with a deeper seated magma reservoir. The anomaly beneath the southern flank of the volcano is limited by the Calambayú Fault and coincides with the dense seismicity cluster. We interpret this anomaly as the pathway of fluids following the weakened rocks along the fault zone. Another anomaly located beneath the main summit of Nevado del Huila probably represents the magma conduit that fed the previous eruption of this volcano. The seismicity here is not as intensive as that beneath the southern flank, which is possibly caused by higher temperature and ductile properties of rocks in the conduit. At depths from 2 to 4 km below surface, we observe the limit between higher Vp/Vs below and lower Vp/Vs above that possibly represents the level of fluid degassing due to decompression.

KW - 3-D velocity structure

KW - Colombia

KW - fluid migration

KW - local earthquake tomography

KW - Nevado del Huila Volcanic Complex

KW - volcanic activity

KW - RUIZ

KW - VELOCITY STRUCTURE

KW - ERUPTION

KW - ALGORITHM

KW - BENEATH

UR - http://www.scopus.com/inward/record.url?scp=85061231286&partnerID=8YFLogxK

U2 - 10.1029/2018JB016324

DO - 10.1029/2018JB016324

M3 - Article

AN - SCOPUS:85061231286

VL - 124

SP - 1688

EP - 1699

JO - Journal of Geophysical Research: Solid Earth

JF - Journal of Geophysical Research: Solid Earth

SN - 2169-9313

IS - 2

ER -