Crater morphology at active volcanoes can change rapidly. Quantifying changes during the course of a volcanic unrest episode may help assess the level of volcanic activity. However, limitations such as crater accessibility, cloud cover or intra-crater eruptive activity may hamper regular optical or on-site crater monitoring. Here we use multi-sensor satellite Synthetic Aperture Radar (SAR) imagery to produce dense time series of quantitative indicators of crater morphological changes. High temporal resolution is achieved by combining images from a variety of sensors and acquisition modes, though the diversity of acquisition geometries (incidence angle, viewing direction, resolution…) prevents direct comparison between the different images. Using basic trigonometry assumptions, we develop PickCraterSAR, an open-access tool written in Python to measure crater radius and depth from SAR amplitude images in radar geometry. We apply our methodology to study the crater collapse associated with the May 2021 and January 2002 eruptions of Nyiragongo volcano. After the 2021 collapse, we estimate the maximum depth of the crater to be 850 m below the rim and the total volume to be 84$\pm$10 Mm$^3$ (270 m deeper but only 15-20 \% more voluminous than the post-2002 eruption crater). We also show that the 2021 crater collapse occurred progressively while a dike intrusion was migrating toward the south.
This archive contains the data necessary to reproduce the results described in "What triggers caldera ring-fault subsidence at Ambrym volcano? Insights from the 2015 dike intrusion and eruption" published in Journal of Geophysical Research - Solid Earth by Tara Shreve, Raphaël Grandin, Delphine Smittarello, Valérie Cayol, Virginie Pinel, Marie Boichu, and Yu Morishita.
Earth and Space Science Open Archive Presented WorkOpen AccessYou are viewing the latest version by default [v1]Propagation and arrest of the May 2021 lateral dike intrusion at Nyiragongo (D.R. Congo)AuthorsDelphineSmittarelloJulienBarrièreiDNicolasd'OreyeiDBenoitSmetsiDAdrienOthTaraShreveiDJosueSubiraBlaiseMafuko NyandwiValerieCayolRaphaelGrandiniDChristelleWauthierDominiqueDerauwHalldorGeirssonNicolasTheysFrançoisDarchambeauSamPoppePatrickAllardCorentinCaudronPhilippeLesageiDSergeySamsonoviDLouiseDelhayeMagdalena OryaëlleChevrelNicheMashagiroAdalbertMuhindo SyavulisemboFrancoisKervynSee all authors Delphine SmittarelloCorresponding Author• Submitting AuthorEuropean Center for Geodynamics and Seismologyview email addressThe email was not providedcopy email addressJulien BarrièreiDEuropean Center for Geodynamics and SeismologyiDhttps://orcid.org/0000-0002-0948-2945view email addressThe email was not providedcopy email addressNicolas d'OreyeiDNational Museum of Natural HistoryiDhttps://orcid.org/0000-0002-3192-448Xview email addressThe email was not providedcopy email addressBenoit SmetsiDRoyal Museum for Central AfricaiDhttps://orcid.org/0000-0002-1044-8314view email addressThe email was not providedcopy email addressAdrien OthEuropean Center for Geodynamics and Seismologyview email addressThe email was not providedcopy email addressTara ShreveiDCarnegie Institution for ScienceiDhttps://orcid.org/0000-0003-2103-2434view email addressThe email was not providedcopy email addressJosue SubiraGoma Volcano Observatoryview email addressThe email was not providedcopy email addressBlaise Mafuko NyandwiRoyal Museum for Central Africaview email addressThe email was not providedcopy email addressValerie CayolLyon Universityview email addressThe email was not providedcopy email addressRaphael GrandiniDUniversité de Paris, Institut de Physique du Globe de Paris, CNRSiDhttps://orcid.org/0000-0002-1837-011Xview email addressThe email was not providedcopy email addressChristelle WauthierThe Pennsylvania State Universityview email addressThe email was not providedcopy email addressDominique DerauwCentre Spatial de Liègeview email addressThe email was not providedcopy email addressHalldor GeirssonUniversity of Icelandview email addressThe email was not providedcopy email addressNicolas TheysRoyal Belgian Institute for Space Aeronomyview email addressThe email was not providedcopy email addressFrançois DarchambeauUniversité de Liègeview email addressThe email was not providedcopy email addressSam PoppeUniversité Libre de Bruxellesview email addressThe email was not providedcopy email addressPatrick AllardCNRSview email addressThe email was not providedcopy email addressCorentin CaudronInstitut de Recherche et de Développement (IRD)view email addressThe email was not providedcopy email addressPhilippe LesageiDISTerre Institute of Earth SciencesiDhttps://orcid.org/0000-0001-5156-5245view email addressThe email was not providedcopy email addressSergey SamsonoviDNatural Resources CanadaiDhttps://orcid.org/0000-0002-6798-4847view email addressThe email was not providedcopy email addressLouise DelhayeRoyal Museum for Central Africaview email addressThe email was not providedcopy email addressMagdalena Oryaëlle ChevrelUniversité Clermont-Auvergneview email addressThe email was not providedcopy email addressNiche MashagiroGoma Volcano Observatoryview email addressThe email was not providedcopy email addressAdalbert Muhindo SyavulisemboGoma Volcano Observatoryview email addressThe email was not providedcopy email addressFrancois KervynRoyal Museum for Central Africaview email addressThe email was not providedcopy email address
Abstract Surface deformation accompanying dike intrusions is dominated by uplift and horizontal motion directly related to the intrusions. In some cases, it includes subsidence due to associated magma reservoir deflation. When reservoir deflation is large enough, it can form, or reactivate preexisting, caldera ring‐faults. Ring‐fault reactivation, however, is rarely observed during moderate‐sized eruptions. On February 21, 2015 at Ambrym volcano in Vanuatu, a basaltic dike intrusion produced more than 1 m of coeruptive uplift, as measured by InSAR, synthetic aperture radar correlation, and Multiple Aperture Interferometry. Here, we show that an average of ∼40 cm of slip occurred on a normal caldera ring‐fault during this moderate‐sized (VEI < 3) event, which intruded a volume of ∼24 × 10 6 m 3 and erupted ∼9.3 × 10 6 m 3 of lava (DRE). Using the 3D Mixed Boundary Element Method, we explore the stress change imposed by the opening dike and the depressurizing reservoir on a passive, frictionless fault. Normal fault slip is promoted when stress is transferred from a depressurizing reservoir beneath one of Ambrym's main craters. After estimating magma compressibility, we provide an upper bound on the critical fraction ( f = 7%) of magma extracted from the reservoir to trigger fault slip. We infer that broad basaltic calderas may form in part by hundreds of subsidence episodes no greater than a few meters, as a result of magma extraction from the reservoir during moderate‐sized dike intrusions.
Earth and Space Science Open Archive This work has been accepted for publication in Journal of Geophysical Research - Solid Earth. Version of RecordESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary. Learn more about preprints. preprintOpen AccessYou are viewing the latest version by default [v2]What triggers caldera ring-fault subsidence at Ambrym volcano? Insights from the 2015 dike intrusion and eruptionAuthorsTaraShreveiDRaphaëlGrandiniDDelphineSmittarelloValérieCayolVirginiePineliDMarieBoichuiDYuMorishitaSee all authors Tara ShreveiDCorresponding Author• Submitting AuthorInstitut de Physique du Globe de ParisCarnegie Institution for ScienceiDhttps://orcid.org/0000-0003-2103-2434view email addressThe email was not providedcopy email addressRaphaël GrandiniDInstitut de Physique du Globe de ParisiDhttps://orcid.org/0000-0002-1837-011Xview email addressThe email was not providedcopy email addressDelphine SmittarelloUniversity Grenoble Alpes, University Savoie Mont BlancEuropean Center for Geodynamics and Seismologyview email addressThe email was not providedcopy email addressValérie CayolLaboratoire Magmas et Volcansview email addressThe email was not providedcopy email addressVirginie PineliDInstitut de Recherche pour le DéveloppementiDhttps://orcid.org/0000-0002-4928-9584view email addressThe email was not providedcopy email addressMarie BoichuiDUniversité de LilleiDhttps://orcid.org/0000-0003-3163-8325view email addressThe email was not providedcopy email addressYu MorishitaGeospatial Information Authority of Japan,Hokkaido Universityview email addressThe email was not providedcopy email address
Eruptive activity shapes volcanic edifices. The formation of broad caldera depressions is often associated with major collapse events, emplacing conspicuous pyroclastic deposits. However, caldera subsidence may also proceed silently by magma withdrawal at depth, more difficult to detect. Ambrym, a basaltic volcanic island, hosts a 12-km wide caldera and several intensely-degassing lava lakes confined to intra-caldera cones. Using satellite remote sensing of deformation, gas emissions and thermal anomalies, combined with seismicity and ground observations, we show that in December 2018 an intra-caldera eruption at Ambrym preceded normal faulting with >2 m of associated uplift along the eastern rift zone and 2.5 m of caldera-wide subsidence. Deformation was caused by lateral migration of >0.4 cubic kilometers of magma into the rift zone, extinguishing the lava lakes, and feeding a submarine eruption in the rift edge. Recurring rifting episodes, favored by stress induced by the D’Entrecasteaux Ridge collision against the New Hebrides arc, lead to progressive subsidence of Ambrym’s caldera and concurrent draining of the lava lakes. Although counterintuitive, convergent margin systems can induce rift zone volcanism and subsequent caldera subsidence.
The following files were used in the analysis from "Trapdoor fault activation: a step towards caldera collapse at Sierra Negra, Galápagos, Ecuador", Journal of Geophysical Research: Solid Earth: alos2_csk/alos2_sm1_dsc_20180504_20180713/: Includes DEM used in processing of the ALOS-2 SM1 descending interferogram spanning 4 May 2018–13 July 2018 (dem.2alks_2rlks.crop.*); geocoded SAR offsets in pixels (range resolution=1.43 m/pixel; azimuth resolution=2.01 m/pixel; denseOffsets.bil.2alks_2rlks.geo*); geocoded SNR of SAR offsets (denseOffsets_snr.bil.2alks_2rlks.geo.*); geocoded, unwrapped interferometric phase (filt_topophase.unw.2alks_2rlks.geo.*); geocoded incidence and heading angle for the interferogram (los.rdr.2alks_2rlks.geo.*); all in ISCE format. alos2_csk/alos2_sm3_asc_20180114_20180701/: Includes DEM used in processing of the ALOS-2 SM3 ascending interferogram spanning 14 January 2018–1 July 2018 (dem.crop.*); geocoded, unwrapped interferometric phase (filt_topophase.unw.geo.*); geocoded incidence and heading angle for the interferogram (los.rdr.geo.*); all in ISCE format. alos2_csk/alos2_wd1_dsc_147_180518_180629/: Includes DEM used in processing of the ALOS-2 WD1 descending interferogram spanning 18 May 2018–29 June 2018 (crop.dem.*); geocoded, unwrapped interferometric phase (filt_180629-180518_2rlks_14alks.unw.geo.*) ; geocoded incidence and heading angle for the interferogram (180629-180518_2rlks_14alks.los.geo.*); geocoded coherence for the interferogram (180629-180518_2rlks_14alks.cor.geo.*); geocoded mask for the interferogram (filt_topophase.unw.masked.geo.*); all in ISCE format. alos2_csk/csk_asc_20180617_20180703/: Includes DEM used in processing of the COSMO-SkyMed ascending interferogram spanning 17 June 2018–3 July 2018 (dem.crop.*); geocoded SAR offsets in pixels (range resolution=1.54 m/pixel; azimuth resolution=2.48 m/pixel; denseOffsets.bil.geo.*); geocoded SNR of SAR offsets (denseOffsets_snr.bil.geo); geocoded incidence and heading angle for the interferogram (los.rdr.geo.*); all in ISCE format. alos2_csk/csk_asc_20180703_20180719/: Includes DEM used in processing of the COSMO-SkyMed ascending interferogram spanning 3 July 2018–19 July 2018 (dem.crop.*); geocoded SAR offsets in pixels (range resolution=1.54 m/pixel; azimuth resolution=2.48 m/pixel; denseOffsets.bil.geo.*); geocoded SNR of SAR offsets (denseOffsets_snr.bil.geo); geocoded incidence and heading angle for the interferogram (los.rdr.geo.*); all in ISCE format. alos2_csk/csk_dsc_20180618_20180704/: Includes DEM used in processing of the COSMO-SkyMed descending interferogram spanning 18 June 2018–4 July 2018 (dem.crop.*); geocoded SAR offsets in pixels (range resolution=1.70 m/pixel; azimuth resolution=2.45 m/pixel; denseOffsets.bil.geo.*); geocoded SNR of SAR offsets (denseOffsets_snr.bil.geo); geocoded incidence and heading angle for the interferogram (los.rdr.geo.*); all in ISCE format. alos2_csk/csk_dsc_20180704_20180720/: Includes DEM used in processing of the COSMO-SkyMed descending interferogram spanning 4 July 2018–20 July 2018 (dem.crop.*); geocoded SAR offsets in pixels (range resolution=1.70 m/pixel; azimuth resolution=2.45 m/pixel; denseOffsets.bil.geo.*); geocoded SNR of SAR offsets (denseOffsets_snr.bil.geo); geocoded incidence and heading angle for the interferogram (los.rdr.geo.*); all in ISCE format. S1.zip: Unwrapped, geocoded interferometric phase in meters for Sentinel-1 ascending and descending interferograms, spanning time periods of interest. S1_20180630_20180706_asc_mask_nan_ref.grd: Unwrapped, geocoded, and masked interferometric phase for Sentinel-1 ascending interferogram spanning 30 June 2018–6 July 2018. S1_20180701_20180707_desc_mask_nan_ref.grd: Unwrapped, geocoded, and masked interferometric phase for Sentinel-1 descending interferogram spanning 1 July 2018–7 July 2018. tandemx12m_crop.grd: TanDEM-X 12 meter DEM in meters. pleaides_tandemx12m_diff.grd: Difference between the TanDEM-X 12 meter DEM and the Pléiades-derived DEM, computed from images on 29 October 2018 and 6 December 2019. trapdoorFaultSlip.zip: Discretized trapdoor fault patch dip-slip modeled to fit deformation from Sentinel-1 ascending interferograms, estimated using the Classic Slip Inversion software. trapdoorFaultTraces.zip: Caldera and trapdoor fault traces, derived from Bell et al. 2021. SN14_tilt_10s_2018-19.txt: Text filt containing date-time (sampled at 10 s, in matplotlib date-time number format), N-S tilt and E-W tilt. Tilt values can be converted to microradians by multiplying by a factor of 0.00129. Tilt data obtained from authors of Bell et al. 2021. For use of this dataset, please cite https://doi.org/10.1038/s41467-021-21596-4.
