{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,7]],"date-time":"2026-02-07T06:41:15Z","timestamp":1770446475350,"version":"3.49.0"},"reference-count":66,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2016,12,24]],"date-time":"2016-12-24T00:00:00Z","timestamp":1482537600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NASA","award":["NNX12AQ38G"],"award-info":[{"award-number":["NNX12AQ38G"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Deformation of pyroclastic flow deposits begins almost immediately after emplacement, and continues thereafter for months or years. This study analyzes the extent, volume, thickness, and variability in pyroclastic flow deposits (PFDs) on Augustine Volcano from measuring their deformation rates with interferometric synthetic aperture radar (InSAR). To conduct this analysis, we obtained 48 SAR images of Augustine Volcano acquired between 1992 and 2010, spanning its most recent eruption in 2006. The data were processed using d-InSAR time-series analysis to measure the thickness of the Augustine PFDs, as well as their surface deformation behavior. Because much of the 2006 PFDs overlie those from the previous eruption in 1986, geophysical models were derived to decompose deformation contributions from the 1986 deposits underlying the measured 2006 deposits. To accomplish this, we introduce an inversion approach to estimate geophysical parameters for both 1986 and 2006 PFDs. Our analyses estimate the expanded volume of pyroclastic flow material deposited during the 2006 eruption to be 3.3 \u00d7 107 m3 \u00b1 0.11 \u00d7 107 m3, and that PFDs in the northeastern part of Augustine Island reached a maximum thickness of ~31 m with a mean of ~5 m. Similarly, we estimate the expanded volume of PFDs from the 1986 eruption at 4.6 \u00d7 107 m3 \u00b1 0.62 \u00d7 107 m3, with a maximum thickness of ~31 m, and a mean of ~7 m.<\/jats:p>","DOI":"10.3390\/rs9010004","type":"journal-article","created":{"date-parts":[[2016,12,28]],"date-time":"2016-12-28T11:22:14Z","timestamp":1482924134000},"page":"4","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Pyroclastic Flow Deposits and InSAR: Analysis of Long-Term Subsidence at Augustine Volcano, Alaska"],"prefix":"10.3390","volume":"9","author":[{"given":"David","family":"McAlpin","sequence":"first","affiliation":[{"name":"Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Franz","family":"Meyer","sequence":"additional","affiliation":[{"name":"Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, USA"},{"name":"Alaska Satellite Facility, Fairbanks, AK 99775, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6806-8974","authenticated-orcid":false,"given":"Wenyu","family":"Gong","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"James","family":"Beget","sequence":"additional","affiliation":[{"name":"Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, USA"},{"name":"Alaska Volcano Observatory, Fairbanks, AK 99775, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Webley","sequence":"additional","affiliation":[{"name":"Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,12,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"9183","DOI":"10.1029\/JB094iB07p09183","article-title":"Mapping small elevation changes over large areas: Differential radar interferometry","volume":"94","author":"Gabriel","year":"1989","journal-title":"J. Geophys. Res."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1029\/97RG03139","article-title":"Radar interferometry and its application to changes in the earth's surfaces","volume":"36","author":"Massonnet","year":"1998","journal-title":"Rev. Geophys."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Mouginis-Mark, P.J., and Domergue-Schmidt, N. (2000). Acquisition of satellite data for volcano studies. Remote Sens. Active Volcanism, 9\u201324.","DOI":"10.1029\/GM116p0009"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1109\/5.838084","article-title":"Synthetic aperture radar interferometry","volume":"88","author":"Rosen","year":"2000","journal-title":"Proc. IEEE"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Masterlark, T., and Lu, Z. (2004). Transient volcano deformation sources imaged with interferometric synthetic aperture radar: Application to Seguam Island, Alaska. J. Geophys. Res. Solid Earth, 109.","DOI":"10.1029\/2003JB002568"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"23109","DOI":"10.1029\/96JE01459","article-title":"Surface deformation and coherence measurements of Kilauea Volcano, Hawaii, from SIR-C radar interferometry","volume":"101","author":"Rosen","year":"1996","journal-title":"J. Geophys. Res. Planets"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Zebker, H.A., Amelung, F., and Jonsson, S. (2000). Remote sensing of volcano surface and internal processes using radar interferometry. Remote Sens. Active Volcanism, 179\u2013205.","DOI":"10.1029\/GM116p0179"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"677","DOI":"10.1016\/S0070-4571(08)71103-8","article-title":"Compaction of ash-flow tuffs","volume":"18","author":"Sheridan","year":"1975","journal-title":"Dev. Sedimentol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1007\/BF00301291","article-title":"Cooling, degassing and compaction of rhyolitic ash flow tuffs: A computational model","volume":"57","author":"Riehle","year":"1995","journal-title":"Bull. Volcanol."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Cas, R.A.F., and Wright, J.V. (1987). Volcanic Successions, Modern and Ancient: A Geological Approach to Processes, Products and Successions, Allen & Unwin, Ltd.","DOI":"10.1007\/978-94-009-3167-1"},{"key":"ref_11","unstructured":"Williams, H., and McBirney, A.R. (1979). Volcanology, Free man, Cooper & Co."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Power, J., Coombs, M.L., and Freymueller, J. (2010). Pyroclastic Flows, Lahars, and Mixed Avalanches Generated During the 2006 Eruption of Augustine Volcano.","DOI":"10.3133\/pp1769"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"11293","DOI":"10.1029\/2000JB900425","article-title":"Surface movements of emplaced lava flows measured by synthetic aperture radar interferometry","volume":"106","author":"Stevens","year":"2001","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Lu, Z., Masterlark, T., and Dzurisin, D. (2005). Interferometric synthetic aperture radar study of Okmok volcano, Alaska, 1992\u20132003: Magma supply dynamics and post-emplacement lava flow deformation. J. Geophys. Res., 110.","DOI":"10.1029\/2004JB003148"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1029\/96GL03705","article-title":"Post-eruptive deformation associated with the 1986\u20131987 and 1989 lava flows of Etna detected by radar interferometry","volume":"24","author":"Briole","year":"1997","journal-title":"Geophys. Res. Lett."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Schmincke, H.U. (2004). Volcanism, Springer.","DOI":"10.1007\/978-3-642-18952-4"},{"key":"ref_17","unstructured":"Waitt, R.B., and Beg\u00e9t, J. (2009). Geologic Map of Augustine Island, Alaska-Plate 1, 1:25,000."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Power, J.A., Coombs, M.L., and Freymueller, J. (2010). Geologic Map of On-Island Deposits from the 2006 Eruption of Augustine Volcano (Map)-Plate 1, 1:20000.","DOI":"10.3133\/pp1769"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Lipman, P.W., and Mullineaux, D.R. (1981). Pyroclastic-flow deposits, The 1980 Eruptions of Mount St. Helens.","DOI":"10.3133\/pp1250"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1016\/j.jvolgeores.2005.07.004","article-title":"Thickness distribution of a cooling pyroclastic flow deposit on Augustine Volcano, Alaska: Optimization using InSAR, FEMs, and an adaptive mesh algorithm","volume":"150","author":"Masterlark","year":"2006","journal-title":"J. Volcanol. Geotherm. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/0377-0273(85)90046-0","article-title":"A reconnaissance of the major Holocene tephra deposits in the upper Cook Inlet region, Alaska","volume":"26","author":"Riehle","year":"1985","journal-title":"J. Volcanol. Geotherm. Res."},{"key":"ref_22","first-page":"435","article-title":"Explosion at dormant Alaskan volcano","volume":"87","author":"Zielinki","year":"2006","journal-title":"Eos. Trans. Am. Geophys. Union"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Neal, C.A., McGimsey, R.G., Dixon, J.P., Manevich, A., and Rybin, A. (2008). 2006 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory.","DOI":"10.3133\/sir20085214"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1016\/0377-0273(79)90051-9","article-title":"Plume dynamics, thermal energy and long-distance transport of vulcanian eruption clouds from Augustine Volcano, Alaska","volume":"6","author":"Kienle","year":"1979","journal-title":"J. Volcanol. Geotherm. Res."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Power, J., Coombs, M.L., and Freymueller, J. (2010). Seismic observations of Augustine Volcano, 1970\u20132007, The 2006 Eruption of Augustine Volcano, Alaska.","DOI":"10.3133\/pp1769"},{"key":"ref_26","unstructured":"Hamilton, T.D., and Galloway, J.P. (1987). The 1986 eruptions of Augustine Volcano, Alaska: Hazards and effects, Geologic Studies in Alaska in 1986."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Miller, T.P., McGimsey, R.G., Richter, D.H., Riehle, J.R., Nye, C.J., Yount, M.E., and Dumoulin, J.A. (1998). Catalog of the Historically Active Volcanoes of Alaska.","DOI":"10.3133\/ofr98582"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Waitt, R.B., and Beg\u00e9t, J. (2009). Volcanic Processes and Geology of Augustine Volcano, Alaska\u2014Plate 2, 1:25,000.","DOI":"10.3133\/pp1762"},{"key":"ref_29","first-page":"232","article-title":"Debris avalanches and lateral blasts at Mount St. Augustine Volcano, Alaska","volume":"5","author":"Siebert","year":"1989","journal-title":"Natl. Geogr. Res."},{"key":"ref_30","first-page":"257","article-title":"Confirmation and calibration of computer modeling of tsunamis produced by Augustine Volcano, Alaska","volume":"24","author":"Kowalik","year":"2006","journal-title":"Sci. Tsunami Hazards"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1126\/science.ns-3.54.186","article-title":"Notes on the eruption of Mount St. Augustine, Alaska, Oct. 6, 1883","volume":"3","author":"Davidson","year":"1884","journal-title":"Science"},{"key":"ref_32","unstructured":"United States Geological Survey (USGS): Geographic Names Information System, Available online: http:\/\/geonames.usgs.gov\/apex\/f?p=136:3:0::NO:3:P3_FID,P3_TITLE:1412986,Nanwalek."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1442","DOI":"10.1126\/science.236.4807.1442","article-title":"Tsunamis generated by eruptions from Mount St. Augustine Volcano, Alaska","volume":"236","author":"Kienle","year":"1987","journal-title":"Science"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Power, J.A., Coombs, M.L., and Freymueller, J. (2010). Timing, distribution, and volume of proximal products of the 2006 eruption of Augustine Volcano, The 2006 Eruption of Augustine Volcano, Alaska.","DOI":"10.3133\/pp1769"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1029\/2006EO370002","article-title":"The reawakening of Alaska\u2019s Augustine Volcano","volume":"87","author":"Power","year":"2006","journal-title":"Eos Trans. AGU"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Cervelli, P.F., Fournier, T., Freymueller, J., and Power, J.A. (2006). Ground deformation associated with the precursory unrest and early phases of the January 2006 eruption of Augustine Volcano, Alaska. Geophys. Res. Lett., 33.","DOI":"10.1029\/2006GL027219"},{"key":"ref_37","unstructured":"Curlander, J.C., and McDonough, R.N. (1991). Synthetic Aperture Radar: Systems and Signal Processing, John Wiley & Sons, Inc."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Power, J.A., Coombs, M.L., and Freymueller, J. (2010). Petrology and geochemistry of the 2006 eruption of Augustine Volcano, The 2006 Eruption of Augustine Volcano, Alaska.","DOI":"10.3133\/pp1769"},{"key":"ref_39","unstructured":"Gardner, C. (2016). Unpublished data."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"896","DOI":"10.1109\/36.239913","article-title":"Change detection techniques for ERS-1 SAR data","volume":"31","author":"Rignot","year":"1993","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"221","DOI":"10.5589\/m04-004","article-title":"An introduction to the RADARSAT-2 mission","volume":"30","author":"Morena","year":"2004","journal-title":"Can. J. Remote Sens."},{"key":"ref_42","unstructured":"European Space Agency: Observing the Earth. Available online: http:\/\/www.esa.int\/Our_Activities\/Observing_the_Earth\/ERS_overview."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"3307","DOI":"10.1109\/TGRS.2007.901027","article-title":"ALOS PALSAR: A pathfinder mission for global-scale monitoring of the environment","volume":"45","author":"Rosenqvist","year":"2007","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"559","DOI":"10.1016\/S0094-5765(01)00020-0","article-title":"The Shuttle Radar Topography Mission (SRTM): A breakthrough in remote sensing of topography","volume":"48","year":"2001","journal-title":"Acta Astronaut."},{"key":"ref_45","unstructured":"Rodriguez, E., Morris, C.S., Belz, J., Chapin, E., Martin, J., Daffer, W., and Hensley, S. (2005). An Assessment of the SRTM Topographic Products, Jet Propulsion Laboratory."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1175","DOI":"10.1002\/2014JB011384","article-title":"Measurement and interpretation of subtle deformation signals at Unimak Island from 2003 to 2010 using weather model-assisted time series InSAR","volume":"120","author":"Gong","year":"2015","journal-title":"J. Geophys. Res. Solid Earth."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"4033","DOI":"10.1109\/TGRS.2015.2389143","article-title":"Temporal filtering of InSAR data using statistical parameters from NWP models","volume":"53","author":"Gong","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"4035","DOI":"10.1029\/1998GL900033","article-title":"Radar interferogram filtering for geophysical applications","volume":"25","author":"Goldstein","year":"1998","journal-title":"Geophys. Res. Lett."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"813","DOI":"10.1109\/36.673674","article-title":"A novel phase unwrapping method based on network programming","volume":"36","author":"Costantini","year":"1998","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"2375","DOI":"10.1109\/TGRS.2002.803792","article-title":"A new algorithm for surface deformation monitoring based on small baseline differential SAR interferograms","volume":"40","author":"Berardino","year":"2002","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1002\/2013EO070001","article-title":"New radar interferometric time series analysis toolbox released","volume":"94","author":"Agram","year":"2013","journal-title":"Eos Trans. Am. Geophys. Union"},{"key":"ref_52","unstructured":"Power, J.A., Coombs, M.L., and Freymueller, J.T. (2010). Surface deformation of Augustine Volcano, 1992\u20132005, from multiple-interferogram processing using a refined small baseline subset (SBAS) interferometric synthetic aperture radar (InSAR) approach, The 2006 Eruption of Augustine Volcano, Alaska."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"4249","DOI":"10.1109\/TGRS.2012.2227761","article-title":"DEM error correction in InSAR time series","volume":"51","author":"Fattahi","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1186\/BF03352811","article-title":"Deformation of the Augustine Volcano, Alaska, 1992\u20132005, measured by ERS and ENVISAT SAR interferometry","volume":"60","author":"Lee","year":"2008","journal-title":"Earth Planets Space"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1016\/j.epsl.2012.04.027","article-title":"Measuring large topographic change with InSAR: Lava thicknesses, extrusion rate, and subsidence rate at Santiaguito Volcano, Guatemala","volume":"335","author":"Ebmeier","year":"2012","journal-title":"Earth Planet. Sci. Lett."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"21483","DOI":"10.1029\/2000JB900200","article-title":"Ground deformation associated with the March 1996 earthquake swarm at Akutan volcano, Alaska, revealed by satellite radar interferometry","volume":"105","author":"Lu","year":"2000","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_57","unstructured":"Lu, Z., Masterlark, T., Wicks, C., Thatcher, W., Dzurisin, D., and Power, J. (2002, January 24\u201328). Interferometric synthetic aperture radar studies of Alaska volcanoes. Proceedings of the IEEE International Geoscience and Remote Sensing Symposium, Toronto, ON, Canada."},{"key":"ref_58","doi-asserted-by":"crossref","unstructured":"Lu, Z., Dzurisin, D., Biggs, J., Wicks, C., and McNutt, S. (2010). Ground surface deformation patterns, magma supply, and magma storage at Okmok volcano, Alaska, from InSAR analysis: 1. Intereruption deformation, 1997\u20132008. J. Geophys. Res., 115.","DOI":"10.1029\/2009JB006969"},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"1541","DOI":"10.1029\/98GL00642","article-title":"Dynamic deformation of Etna Volcano observed by satellite radar interferometry","volume":"25","author":"Lanari","year":"1998","journal-title":"Geophys. Res. Lett."},{"key":"ref_60","first-page":"9","article-title":"Interferometric synthetic aperture radar studies of Alaska volcanoes","volume":"12","author":"Lu","year":"2003","journal-title":"Earth Obs. Mag."},{"key":"ref_61","doi-asserted-by":"crossref","unstructured":"Pauk, B.A., Power, J.A., Lisowski, M., Dzurisin, D., Iwatsubo, E.Y., and Melbourne, T. (2001). Global Positioning System (GPS) Survey of Augustine Volcano, Alaska, August 3\u20138, 2000: Data Processing, Geodetic Coordinates, and Comparison with Prior Geodetic Surveys.","DOI":"10.3133\/ofr0199"},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1093\/biomet\/37.1-2.149","article-title":"Some theorems in least squares","volume":"37","author":"Plackett","year":"1950","journal-title":"Biometrika"},{"key":"ref_63","unstructured":"Japan Aerospace Exploration Agency: DAICHI (ALOS) Operation Completion. Available online: http:\/\/www.jaxa.jp\/press\/2011\/05\/20110512_daichi_e.html."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"4500","DOI":"10.1029\/JB093iB05p04500","article-title":"The 1986 eruption of Mount St. Augustine: Field test of a hazard evaluation","volume":"93","author":"Swanson","year":"1988","journal-title":"J. Geophys. Res."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1016\/0377-0273(89)90098-X","article-title":"Density and void ratio on emplacement of a small pyroclastic flow, Mount St. Augustine, Alaska","volume":"39","author":"Limke","year":"1989","journal-title":"J. Volcanism Geotherm. Res."},{"key":"ref_66","doi-asserted-by":"crossref","unstructured":"Masterlark, T. (2003). Finite element model predictions of static deformation from dislocation sources in a subduction zone: Sensitivities to homogeneous, isotropic, Poisson-solid, and half-space assumptions. J. Geophys. Res. Solid Earth, 108.","DOI":"10.1029\/2002JB002296"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/1\/4\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:29:15Z","timestamp":1760210955000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/1\/4"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,12,24]]},"references-count":66,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2017,1]]}},"alternative-id":["rs9010004"],"URL":"https:\/\/doi.org\/10.3390\/rs9010004","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,12,24]]}}}