GregCocks, 4 months ago to Geology Major Fluvial Erosion And A 500-Mt Sediment Pulse Triggered By Lava-Dam Failure, Río Coca, Ecuador https://doi.org/10.1002/esp.5751 <-- shared paper #GIS #spatial #mapping #hydrology #erosion #volcanic #landscape #fluvial #risk #hazard #sediment #lava #dam #failure #RioCoca #ecuador #watershed #massmovement #scouring #river #model #modeling #geotechnical #geology #geomorphology #geomorphometry #tributaries #waterfall #naturalhazard #naturaldisaster #waterquality #publicsafety #economy #infrastructure #autogenic #volcaniclandscapes photos - Former location of the Cascada San Rafael lava-dam waterfall and knickpoint on the Río Coca, viewed facing upstream. (a) Pre-collapse morphology of the waterfall, in 2012 (image from Ecuador Ministry of Tourism). Accommodation space upstream of the lava dam was filled with sediment. (b) The site was on 2 February 2020, shortly after a sinkhole (upstream of lava dam) captured the river. Dashed line shows the approximate location of the unconformable contact between the lava flow and underlying volcaniclastic avalanche deposits. (c) The site was on 22 February 2021 during the incipient collapse of the remaining arched edifice of the lava flow. (d) Later on 22 February 2021 after full collapse of the lava arch. (e) The site on 25 February 2021, shortly after the river overtopped and eroded through the debris dam. Photographs in (b) through (e) provided by the Corporacion Electrica del Ecuador. map and chart - (a) Detailed map of the study reach (shown within box in Figure 1a), with river kilometres (rkm) shown referring to distance downstream of the Coca Codo Sinclair (CCS) dam and diversion intake. (b) Subsurface geologic cross-section of the study reached from rkm 0 to 22 (annotated using field observations of the authors and borehole information from INECEL [Instituto Ecuatoriano de Electrificacion], 1992). Dashed line shows the riverbed profile as of 2 December 2022, 1,034 days after the failure of the Cascada San Rafael knickpoint. Prior to the loss of the knickpoint in February 2020, the accommodation space upstream of the Cascada San Rafael had entirely filled with sediment. Geologic units are abbreviated as volcaniclastic breccia (Br), cohesive volcaniclastic avalanche deposits (CoAv), loose volcaniclastic avalanche deposits (LoAv), ancient alluvial deposits (All), lacustrine sediments (Lac), debris-flow deposits (Deb, a thin deposit around rkm 8–8.5). Lava flow, recent alluvial deposits and Mesozoic bedrock are also shown. photo - waterfall, Río Coca, Ecuador before failure & erosion
#GIS #spatial #mapping #hydrology #erosion #volcanic #landscape #fluvial #risk #hazard #sediment #lava #dam #failure #RioCoca #ecuador #watershed #massmovement #scouring #river #model #modeling #geotechnical #geology #geomorphology #geomorphometry #tributaries #waterfall #naturalhazard #naturaldisaster #waterquality #publicsafety #economy #infrastructure #autogenic #volcaniclandscapes
photos - Former location of the Cascada San Rafael lava-dam waterfall and knickpoint on the Río Coca, viewed facing upstream. (a) Pre-collapse morphology of the waterfall, in 2012 (image from Ecuador Ministry of Tourism). Accommodation space upstream of the lava dam was filled with sediment. (b) The site was on 2 February 2020, shortly after a sinkhole (upstream of lava dam) captured the river. Dashed line shows the approximate location of the unconformable contact between the lava flow and underlying volcaniclastic avalanche deposits. (c) The site was on 22 February 2021 during the incipient collapse of the remaining arched edifice of the lava flow. (d) Later on 22 February 2021 after full collapse of the lava arch. (e) The site on 25 February 2021, shortly after the river overtopped and eroded through the debris dam. Photographs in (b) through (e) provided by the Corporacion Electrica del Ecuador. map and chart - (a) Detailed map of the study reach (shown within box in Figure 1a), with river kilometres (rkm) shown referring to distance downstream of the Coca Codo Sinclair (CCS) dam and diversion intake. (b) Subsurface geologic cross-section of the study reached from rkm 0 to 22 (annotated using field observations of the authors and borehole information from INECEL [Instituto Ecuatoriano de Electrificacion], 1992). Dashed line shows the riverbed profile as of 2 December 2022, 1,034 days after the failure of the Cascada San Rafael knickpoint. Prior to the loss of the knickpoint in February 2020, the accommodation space upstream of the Cascada San Rafael had entirely filled with sediment. Geologic units are abbreviated as volcaniclastic breccia (Br), cohesive volcaniclastic avalanche deposits (CoAv), loose volcaniclastic avalanche deposits (LoAv), ancient alluvial deposits (All), lacustrine sediments (Lac), debris-flow deposits (Deb, a thin deposit around rkm 8–8.5). Lava flow, recent alluvial deposits and Mesozoic bedrock are also shown. photo - waterfall, Río Coca, Ecuador before failure & erosion