Changes in crater morphology associated with volcanic activity at Telica Volcano, Nicaragua
The formation of volcanic calderas and pit craters is often caused by the collapse of a volcanic edifice following evacuation of magma from a shallow crustal reservoir. Recent dramatic examples from Piton de la Fournaise (Reunion Island), Bárðarbunga (Iceland), and Kilauea (Hawai’i) allowed for quantification of this process. These examples involve change with effusive eruptive activity; however, small spatiotemporal morphologic change related to background persistent and low-level explosive activity has not been well quantified and analyzed in volcanic craters. Telica volcano is a persistently restless basaltic-andesite stratovolcano in Nicaragua. Persistent restlessness at Telica is caused by a long-lived magmatic-hydrothermal system, manifest as high-temperature crater fumaroles and low-frequency seismicity, and is punctuated by sub-decadal, low explosivity (VEI 1-2) phreatic eruptions. We use photographic observations (1994 to 2017) and structure-from-motion (SfM) point cloud construction and differencing (2011 to 2017) to analyze changes at Telica in the context of sustained summit crater formation and eruptive pre-cursors. Material collapse is spatially correlated with long-lived high temperature fumaroles located in the crater walls, while eruptions remove material from the crater floor through vent formation and/or clearing. These patterns of change sustain a morphology similar to those of commonly recognized calderas or pit craters, but without a shallow depressurized magma chamber. Though landslide talus covers the vent prior to eruptions, observed fumaroles provide pressure release that negates shallow vent-blocking landslide talus as the primary sealing mechanism prior to eruption. This study shows promise for photogrammetric techniques in correlating morphologic change with summit crater formation and volcanic activity, and the power of long-term visual observations in understanding active volcanic processes.
|Changes in crater morphology associated with volcanic activity at Telica Volcano, Nicaragua
|Photogrammetric point clouds from structure form motion from 2011-2017
|CC BY 4.0 (Attribution)
|May 01, 2020
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