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Constraints on Absolute Magma Chamber Volume From Geodetic Measurements of Trapdoor Faulting at Sierra Negra Volcano, Galapagos

Zheng, Yujie and Blackstone, Laura and Segall, Paul (2022) Constraints on Absolute Magma Chamber Volume From Geodetic Measurements of Trapdoor Faulting at Sierra Negra Volcano, Galapagos. Geophysical Research Letters, 49 (5). Art. No. e2021GL095683. ISSN 0094-8276. doi:10.1029/2021gl095683.

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Magma chamber volume is critical for volcano hazards assessment and forecasting. Standard geodetic methods constrain volume change, not the total volume. Here, we show that the deformation response of the magma chamber to trapdoor faulting events at Sierra Negra volcano, Galapagos, depends on the product of the absolute chamber volume and the magma compressibility. Bubble-free magma provides the lower limit on compressibility, thus an upper bound on the chamber volume of 13.6–20.6 km3, depending on fault dip. We estimate an upper limit on compressibility using a conduit model relating volatile content to lava fountain height, compared with observations from the 2005 eruption, constrained by volatile content of olivine melt inclusions. This yields a lower bound on chamber volume roughly half the upper bound. We find that the best fitting trapdoor fault is near-vertical; reverse dips are slightly favored (88°).

Item Type:Article
Related URLs:
URLURL TypeDescription and GPS data
Zheng, Yujie0000-0001-9013-451X
Blackstone, Laura0000-0001-7293-9373
Segall, Paul0000-0001-5973-471X
Additional Information:© 2022 American Geophysical Union. Issue Online: 04 March 2022; Version of Record online: 04 March 2022; Accepted manuscript online: 21 February 2022; Manuscript accepted: 12 February 2022; Manuscript revised: 08 February 2022; Manuscript received: 05 October 2021. The research was supported by grants from the National Science Foundation Division of Earth Science (EAR-1829763). The authors would like to thank helpful discussions with Dennis Geist, Mike Stock and others, and thoughtful reviews from William Chadwick and Freysteinn Sigmundsson. Data Availability Statement: The InSAR and GPS data used can be downloaded from
Funding AgencyGrant Number
Subject Keywords:Magma chamber volume; remote sensing; stress interaction
Issue or Number:5
Record Number:CaltechAUTHORS:20220222-707140000
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Official Citation:Zheng, Y., Blackstone, L., & Segall, P. (2022). Constraints on absolute magma chamber volume from geodetic measurements of trapdoor faulting at Sierra Negra volcano, Galapagos. Geophysical Research Letters, 49, e2021GL095683.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113534
Deposited By: George Porter
Deposited On:22 Feb 2022 23:19
Last Modified:22 Mar 2022 20:39

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