Drift River Research Articles

Seasonal Exchanges of Salt and Suspended Particulates between the Sol Bay and the Pará River, Amazonian Coast

Mascarenhas, A.C.C.; Correa, A.W.R.; Carneiro, A.C.; Costa, M.S.; Rollnic, M., and Medeiros, C., 2018. Seasonal Exchanges of Salt and Suspended Particulates between the Sol Bay and the Para River, Amazonian Coast. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 111–115. Coconut Creek (Florida), ISSN 0749-0208.Salt and suspended particulate matter (SPM) exchange between the Sol Bay and the Para River and their tidal/seasonal variability was investigated along the interface cross-section (1°4′30.37″S 48°19′37.48″W), over spring tidal cycles, during the wet (Apr/2015) and dry (Oct/2015) seasons. Advective transport of salt and SPM was analyzed to evaluate trends and contributions of involved mechanism. Overall, salinity was low (S<2) during dry and absent during the wet season. Mean SPM concentrations where higher at flood tides during both seasons. Higher flow velocities were 1.29 m.s−1 (ebb/wet) and 1.17 m.s−1 (flood/dry). During the dry season net salt transport was 8.10 kg.s−1 seawards mainly due to a baywards Stokes drift transport (−193.7 kg.s−1) against a seawards transport by the river discharge, tidal correlation and turbulent shear components ( 179.0; 11.98; 7.72 kg.s−1). However, SPM was stored into Sol Bay at a rate of 2.06 kg.s−1 (90 ton per tidal cycle), as result of the baywards transport by the Stokes drift river discharge (−3.14; −0.82 kg.s−1) in opposition to the seawards transport due to gravitational circulation tidal correlation components ( 1.69; 0.48 kg.s−1). During the wet season the river discharge (29.8 kg.s−1) fluxes out SPM from Sol Bay while the Stokes drift (3.19 kg.s−1) and the turbulent shear (0.65 kg.s−1) components tends to move SPM back into the bay with a net exportation of SPM to the Para River of 26 kg.s−1 (129.8 ton per tidal cycle). In conclusion, matter exchange between the Sol Bay and the Para River is mainly governed by the river discharge and Stokes drift flow components. The relative contributions by the gravitation circulation, tidal correlation and turbulent shear tend to increase under low river discharge. A small salt exportation ( 8.10 kg.s−1) during the dry season

Multi-sensor data fusion for remote sensing of post-eruptive deformation and depositional features at Redoubt Volcano

Monitoring volcanic activity by remote sensing is an essential component of volcanology. Remote sensing includes a variety of different sensing methods and instruments that collect data across a wide range of the electromagnetic spectrum. This study presents an overview of the improvements that are available to remote sensing imaging with multi-sensor and multi-temporal data fusion of optical and radar data, using Redoubt Volcano and related 2009 Drift River lahar deposits as a target area. From ALOS-PRISM data, high resolution DEMs were produced and used to generate elevation change maps of Redoubt Volcano and the Drift River, and to estimate the volcano's dome volume; these DEMs were then fused with ALOS-PALSAR radar images to produce differential interferograms demonstrating the effect of high-resolution DEMs on surface deformation measurements from interferometric radar data; and finally, multi-temporal InSAR coherence data were used to plot the boundaries of lahar flows at the distal end of the Drift River with high accuracy. These techniques demonstrate: (1) how the fusion of data from multiple sensors acquired at multiple temporal intervals can substantially increase the accuracy and precision of remote sensing measurements compared to those from one sensor alone; (2) how data fusion techniques can improve remote sensing change detection in areas otherwise ill-suited for single sensor observations; and (3) how data subject to temporal decorrelation may be used for boundary mapping with high accuracy. In addition to volcanic deformation, these methods can be applied to a number of disciplines, and will become more essential as the number of earth observing satellites increase.

An overview of the 2009 eruption of Redoubt Volcano, Alaska

In March 2009, Redoubt Volcano, Alaska erupted for the first time since 1990. Explosions ejected plumes that disrupted international and domestic airspace, sent lahars more than 35km down the Drift River to the coast, and resulted in tephra fall on communities over 100km away. Geodetic data suggest that magma began to ascend slowly from deep in the crust and reached mid- to shallow-crustal levels as early as May, 2008. Heat flux at the volcano during the precursory phase melted ~4% of the Drift glacier atop Redoubt's summit. Petrologic data indicate the deeply sourced magma, low-silica andesite, temporarily arrested at 9–11km and/or at 4–6km depth, where it encountered and mixed with segregated stored high-silica andesite bodies. The two magma compositions mixed to form intermediate-silica andesite, and all three magma types erupted during the earliest 2009 events. Only intermediate- and high-silica andesites were produced throughout the explosive and effusive phases of the eruption. The explosive phase began with a phreatic explosion followed by a seismic swarm, which signaled the start of lava effusion on March 22, shortly prior to the first magmatic explosion early on March 23, 2009 (UTC). More than 19 explosions (or “Events”) were produced over 13days from a single vent immediately south of the 1989–90 lava domes. During that period multiple small pyroclastic density currents flowed primarily to the north and into glacial ravines, three major lahars flooded the Drift River Terminal over 35km down-river on the coast, tephra fall deposited on all aspects of the edifice and on several communities north and east of the volcano, and at least two, and possibly three lava domes were emplaced. Lightning accompanied almost all the explosions.A shift in the eruptive character took place following Event 9 on March 27 in terms of infrasound signal onsets, the character of repeating earthquakes, and the nature of tephra ejecta. More than nine additional explosions occurred in the next two days, followed by a hiatus in explosive activity between March 29 and April 4. During this hiatus effusion of a lava dome occurred, whose growth slowed on or around April 2. The final explosion pulverized the very poorly vesicular dome on April 4, and was immediately followed by the extrusion of the final dome that ceased growing by July 1, 2009, and reached 72Mm3 in bulk volume. The dome remains as of this writing. Effusion of the final dome in the first month produced blocky intermediate- to high-silica andesite lava, which then expanded by means of lava injection beneath a fracturing and annealing, cooling surface crust. In the first week of May, a seismic swarm accompanied extrusion of an intermediate- to high-silica andesite from the apex of the dome that was highly vesicular and characterized by lower P2O5 content. The dome remained stable throughout its growth period likely due to combined factors that include an emptied conduit system, steady degassing through coalesced vesicles in the effusing lava, and a large crater-pit created by the previous explosions. We estimate the total volume of erupted material from the 2009 eruption to be between ~80M and 120Mm3 dense-rock equivalent (DRE).The aim of this report is to synthesize the results from various datasets gathered both during the eruption and retrospectively, and which are represented by the papers in this publication. We therefore provide an overall view of the 2009 eruption and an introduction to this special issue publication.

Voluminous ice-rich and water-rich lahars generated during the 2009 eruption of Redoubt Volcano, Alaska

Redoubt Volcano in south-central Alaska began erupting on March 15, 2009, and by April 4, 2009, had produced at least 20 explosive events that generated multiple plumes of ash and numerous lahars. The 3108-m-high, snow- and ice-clad stratovolcano has an ice-filled summit crater that is breached to the north. The volcano supports about 4km3 of ice and snow and about 1km3 of this makes up the Drift glacier on the north side of the volcano. Explosive eruptions between March 23 and April 4, which included the destruction of at least two lava domes, triggered significant lahars in the Drift River valley on March 23 and April 4, and several smaller lahars between March 24 and March 31. Mud-line high-water marks, character of deposits, areas of inundation, and estimates of flow velocity revealed that the lahars on March 23 and April 4 were the largest of the eruption. In the 2-km-wide upper Drift River valley, average flow depths were at least 2–5m. Average peak-flow velocities were likely between 10 and 15ms−1, and peak discharges were on the order of 104–105m3s−1. The area inundated by lahars on March 23 was at least 100km2 and on April 4 about 125km2. Two substantial lahars emplaced on March 23 and one on April 4 had volumes on the order of 107–108m3 and were similar in size to the largest lahar of the 1989–90 eruption. The two principal March 23 lahars were primarily flowing slurries of snow and ice derived from Drift glacier and the Drift River valley where seasonal snow and tabular blocks of river ice were entrained and incorporated into the lahars. Despite morphologic evidence of two lahars, only a single deposit up to 5m thick was found in most places and it contained about 80–95% of poorly sorted, massive to imbricate assemblages of snow and ice clasts. The deposit was frozen soon after it was emplaced and later eroded and buried by the April 4 lahar. The lahar of April 4, in contrast, was primarily a hyperconcentrated flow, as interpreted from 1- to 6-m-thick deposits of massive to horizontally stratified sand to fine gravel. Rock material in the April 4 lahar deposit is predominantly juvenile andesite, whereas rock material in the March 23 deposit is rare and not obviously juvenile. We infer that the lahars generated on March 23 were initiated by a rapid succession of vent-clearing explosions that blasted through about 50–100m of crater-filling glacier ice and snow, producing a voluminous release of meltwater from Drift glacier. The resulting surge of water entrained snow, fragments of glacier and river ice, and river water along its flow path. Small-volume pyroclastic flows, possibly associated with destruction of a small dome or minor eruption-column collapses, may have contributed additional meltwater to the March 23 lahars. Meltwater generated by subglacial hydrothermal activity and stored beneath Drift glacier may have been ejected or released rapidly as well. The April 4 lahar was initiated when hot dome-collapse pyroclastic flows entrained and swiftly melted snow and ice on Drift glacier. The resulting meltwater incorporated pyroclastic debris and rock material from Drift glacier to form the largest lahar of the 2009 eruption. The peak discharge of the April 4 lahar was in the range of 60,000–160,000m3s−1. For comparison, the largest lahar of the 1989–90 eruption had a peak discharge of about 80,000m3s−1. Lahars generated by the 2009 eruption led to significant channel aggradation in the lower Drift River valley and caused extensive inundation at an oil storage and transfer facility located there. The April 4, 2009, lahar was 6–30 times larger than the largest meteorological floods known or estimated in the Drift River drainage.

The seismicity of the 2009 Redoubt eruption

Redoubt Volcano erupted in March 2009 following 6months of precursory seismic activity. The 4.5-month-long eruptive sequence was accompanied by phreatic and magmatic explosions, periods of steady dome growth, lahars, seismic swarms, extended episodes of volcanic tremor and changes in the background seismicity rate. This study presents a seismic chronology of the eruption and places it in context with the variety of other geological and geophysical data that were recorded during the eruptive period. We highlight 6 notable seismic swarms, 3 of which preceded large explosions. The swarms varied from an hour to several days in duration, and contained tens to over 7000 earthquakes. Many of the swarms were dominated by low frequency type earthquakes that contained families of repeating events. Seismic tremor varied considerably in frequency, amplitude and duration during the eruption with distinct characteristics accompanying different types of volcanic activity. The explosion signals during March 23–24 were the most energetic, and the explosions on March 26–29 contained proportionally more low frequency energy (0.033–0.3Hz). Two seismic stations were particularly well-suited to recording lahars that flowed down the Drift River valley. Data from these stations showed that lahars were generated by the majority of the explosion events, as well as during the continuous eruptive activity on March 29 when no large explosions occurred. We also examine the seismicity which occurred outside of the explosion and swarm episodes, and find several families of repeating VT earthquakes which begin shortly before the April 4 explosion and that continue through May 2009, locating between 3 and 6km below sea level.

RESEARCH: Effects of Recent Volcanic Eruptions on Aquatic Habitat in the Drift River, Alaska, USA: Implications at Other Cook Inlet Region Volcanoes.

/ Numerous drainages supporting productive salmon habitat are surrounded by active volcanoes on the west side of Cook Inlet in south-central Alaska. Eruptions have caused massive quantities of flowing water and sediment to enter the river channels emanating from glaciers and snowfields on these volcanoes. Extensive damage to riparian and aquatic habitat has commonly resulted, and benthic macroinvertebrate and salmonid communities can be affected. Because of the economic importance of Alaska's fisheries, detrimental effects on salmonid habitat can have significant economic implications. The Drift River drains glaciers on the northern and eastern flanks of Redoubt Volcano. During and following eruptions in 1989-1990, severe physical disturbances to the habitat features of the river adversely affected the fishery. Frequent eruptions at other Cook Inlet region volcanoes exemplify the potential effects of volcanic activity on Alaska's important commercial, sport, and subsistence fisheries. Few studies have documented the recovery of aquatic habitat following volcanic eruptions. The eruptions of Redoubt Volcano in 1989-1990 offered an opportunity to examine the recovery of the macroinvertebrate community. Macroinvertebrate community composition and structure in the Drift River were similar in both undisturbed and recently disturbed sites. Additionally, macroinvertebrate samples from sites in nearby undisturbed streams were highly similar to those from some Drift River sites. This similarity and the agreement between the Drift River macroinvertebrate community composition and that predicted by a qualitative model of typical macroinvertebrate communities in glacier-fed rivers indicate that the Drift River macroinvertebrate community is recovering five years after the disturbances associated with the most recent eruptions of Redoubt Volcano. KEY WORDS: Aquatic habitat; Volcanoes; Lahars; Lahar-runout flows; Macroinvertebrates; Community structure; Community composition; Taxonomic similarity

Hydrologic hazards in the lower Drift River basin associated with the 1989–1990 eruptions of Redoubt Volcano, Alaska

The eruptions of Redoubt Volcano between December 14, 1989 and April 26, 1990 triggered flows of snow, ice, water, sediment, and debris that traveled down the Drift River as far as its mouth, about 40 km downstream. A major explosive eruption and dome collapse on January 2, 1990 produced the largest flow. The peak discharge of this flow at a location 22 km downstream from the volcano was estimated to be between 12,000 and 60,000 m 3 per second. The estimated peak discharge of this event is more than 100 times larger than the 100-year meteorologically generated flood estimated for the Drift River. Pyroclastic flows and hot meltwater scoured the surface of Drift Glacier on the north flank of the volcano and were transformed into multipulsed, multiphased debris flows. Several other significant flows were generated by eruptions during this period: the two largest of these occurred on December 15, 1989 and February 15, 1990. Subsequent channel changes threatened the Drift River Oil Terminal built on an alluvial fan near the mouth of the Drift River.

Postglacial eruption history of Redoubt Volcano, Alaska

Volcaniclastic deposits preserved in valleys on the flanks of Redoubt Volcano comprise a record of the volcano's postglacial eruption history. The oldest and largest deposit is the Harriet Point debris avalanche, emplaced more than 10,500 yr B.P. This debris avalanche travelled more than 30 km down the Redoubt Creek valley to Cook Inlet. About 3600 yr B.P., a massive slope failure of Redoubt Volcano produced at least two lahars that travelled 30 km down the Crescent River valley (Riehle et al., 1981). A series of smaller eruptions between ca. 3600-1800 yr B.P. generated additional lahars and floods that affected the upper Crescent River valley. A pyroclastic fan on the south flank of Redoubt Volcano probably also formed during this time interval. Sometime between 1000 and 300 yr B.P., hydrothermally altered debris collapsed from the summit edifice, and produced a large lahar that travelled more than 30 km down the Drift River valley. At least 5–6 eruptions in the last 250–300 years have produced lahars and floods large enough to impact the site of the Drift River Terminal on the lower Drift River fan. If the eruptive pattern of the last several centuries continues, another eruption is likely sometime in the next 25–100 years. The Holocene eruptions produced calc-alkaline high-silica andesite and dacite, although quenched andesite and basaltic inclusions record the presence of more mafic magmas. Chemical discontinuities indicate that small, chemically discrete batches of magma fed individual eruptions. Progressive enrichments of highly incompatible trace elements presumably reflect crustal contamination of Holocene magmas.

Disruption of Drift glacier and origin of floods during the 1989–1990 eruptions of Redoubt Volcano, Alaska

Melting of snow and glacier ice during the 1989–1990 eruption of Redoubt Volcano caused winter flooding of the Drift River. Drift glacier was beheaded when 113 to 121 × 10 6 m 3 of perennial snow and ice were mechanically entrained in hot-rock avalanches and pyroclastic flows initiated by the four largest eruptions between 14 December 1989 and 14 March 1990. The disruption of Drift glacier was dominated by mechanical disaggregation and entrainment of snow and glacier ice. Hot-rock avalanches, debris flows, and pyroclastic flows incised deep canyons in the glacier ice thereby maintaining a large ice-surface area available for scour by subsequent flows. Downvalley flow rheologies were transformed by the melting of snow and ice entrained along the upper and middle reaches of the glacier and by seasonal snowpack incorporated from the surface of the lower glacier and from the river valley. The seasonal snowpack in the Drift River valley contributed to lahars and floods a cumulative volume equivalent to about 35 × 10 6 m 3 of water, which amounts to nearly 30% of the cumulative flow volume 22 km downstream from the volcano. The absence of high-water marks in depressions and of ice-collapse features in the glacier indicated that no large quantities of meltwater that could potentially generate lahars were stored on or under the glacier; the water that generated the lahars that swept Drift River valley was produced from the proximal, eruption-induced volcaniclastic flows by melting of snow and ice.

Proximal pyroclastic deposits from the 1989–1990 eruption of Redoubt Volcano, Alaska — stratigraphy, distribution, and physical characteristics

More than 20 eruptive events during the 1989–1990 eruption of Redoubt Volcano emplaced a complex sequence of lithic pyroclastic-flow, -surge, -fall, ice-diamict, and lahar deposits mainly on the north side of the volcano. The deposits record the changing eruption dynamics from initial gas-rich vent-clearing explosions to episodic gas-poor lava-dome extrusions and failures. The repeated dome failures produced lithic pyroclastic flows that mixed with snow and glacial ice to generate lahars that were channelled off Drift glacier into the Drift River valley. Some of the dome failures occurred without precursory seismic warning and appeared to result solely from gravitational instability. Material from the disrupted lava domes avalanched down a steep, partly ice-filled canyon incised on the north flank of the volcano and came to rest on the heavily crevassed surface of the piedmont lobe of Drift glacier. Most dome-collapse events resulted in single, monolithologic, massive to reversely graded, medium- to coarse-grained, sandy pyroclastic-flow deposits containing abundant dense dome clasts. These deposits vary in thickness, grain size, and texture depending on distance from the vent and local topography; deposits are finer and better sorted down flow, thinner and finer on hummocks, and thicker and coarser where ponded in channels cut through the glacial ice. The initial vent-clearing explosions emplaced unusual deposits of glacial ice, snow, and rock in a frozen matrix on the north and south flanks of the volcano. Similar deposits were described at Nevado del Ruiz, Columbia and have probably been emplaced at other snow-and-ice-clad volcanoes, but poor preservation makes them difficult to recognize in the geologic record. In a like fashion, most deposits from the 1989–1990 eruption of Redoubt Volcano may be difficult to recognize and interpret in the future because they were emplaced in an environment where glacio-fluvial processes dominate and quickly obscure the primary depositional record.

Flood generation and destruction of “Drift” Glacier by the 1989–90 eruption of Redoubt Volcano, Alaska

Mid -winter flooding of the Drift River was caused by melting of snow and glacier ice during the 1989–90 eruption of Redoubt Volcano. “Drift” Glacier (unofficial name) was beheaded when 110 to 120 × 106m3of perennial snow and ice were mechanically entrained by the four largest volcanically initiated flows. The flow volumes were increased by incorporation of the seasonal snowpack on the lower glacier surface and in the flooded river valley. The seasonal snow contributed a volume equivalent to about 35 × 106m3of water to the flows, increasing the cumulative flood volume by almost 30%. No large amounts of meltwater were stored on or under the glacier before any of the flows took place. The threat of flooding was significantly reduced after the second major eruption removed the remainder of the easily erodible snow and ice.

Flood generation and destruction of “Drift” Glacier by the 1989–90 eruption of Redoubt Volcano, Alaska

Mid -winter flooding of the Drift River was caused by melting of snow and glacier ice during the 1989–90 eruption of Redoubt Volcano. “Drift” Glacier (unofficial name) was beheaded when 110 to 120 × 106 m3 of perennial snow and ice were mechanically entrained by the four largest volcanically initiated flows. The flow volumes were increased by incorporation of the seasonal snowpack on the lower glacier surface and in the flooded river valley. The seasonal snow contributed a volume equivalent to about 35 × 106 m3 of water to the flows, increasing the cumulative flood volume by almost 30%. No large amounts of meltwater were stored on or under the glacier before any of the flows took place. The threat of flooding was significantly reduced after the second major eruption removed the remainder of the easily erodible snow and ice.

Effects of the 1966–68 Eruptions of Mount Redoubt on the Flow of Drift Glacier, Alaska, U.S.A.

AbstractMount Redoubt, a volcano located west of Cook Inlet in Alaska, erupted from 1966 to 1968. This eruptive cycle removed about 6 × 107m3of glacier ice from the upper part of Drift Glacier and decoupled it from the lower part during a sequence of jökulhlaups which originated in the Summit Crater and flooded Drift River. The same events blanketed the lower part of the glacier with sand and ash, reducing ice ablation. Normal snowfall, augmented by intense avalanching, regenerated the upper part of the glacier by 1976, 8 years after the eruptions. When the regenerated glacier connected with the rest of Drift Glacier, it triggered a kinematic wave of thickening ice accompanied by accelerating surface velocities in the lower part of the glacier. Surface velocities increased by an order of magnitude and were accompanied by thickening of 70 m or more. At the same time, parts of the upper glacier thinned 70 m. The glacier appears to be returning to its pre-eruption equilibrium condition.

Effects of the 1966–68 Eruptions of Mount Redoubt on the Flow of Drift Glacier, Alaska, U.S.A.

AbstractMount Redoubt, a volcano located west of Cook Inlet in Alaska, erupted from 1966 to 1968. This eruptive cycle removed about 6 × 107 m3 of glacier ice from the upper part of Drift Glacier and decoupled it from the lower part during a sequence of jökulhlaups which originated in the Summit Crater and flooded Drift River. The same events blanketed the lower part of the glacier with sand and ash, reducing ice ablation. Normal snowfall, augmented by intense avalanching, regenerated the upper part of the glacier by 1976, 8 years after the eruptions. When the regenerated glacier connected with the rest of Drift Glacier, it triggered a kinematic wave of thickening ice accompanied by accelerating surface velocities in the lower part of the glacier. Surface velocities increased by an order of magnitude and were accompanied by thickening of 70 m or more. At the same time, parts of the upper glacier thinned 70 m. The glacier appears to be returning to its pre-eruption equilibrium condition.

Developments in Alaska in 1966

Exploration and development in Alaska during 1966 reached maximum activity. Exploratory drilling resulted in 5 new-field discoveries, 1 new-pool discovery, and 6 successful extensions out of 36 wells drilled. Success was limited to the Cook Inlet basin and the discovery rate decreased from 52% in 1965 to 30% in 1966. Particularly important was the confirmation of the McArthur River field as a giant oil field comparable to Swanson River, Middle Ground Shoal, and Granite Point. Seismic activity increased 31% from 1965. Extensive joint marine surveys were conducted in the Bristol Bay, lower Cook Inlet, and the Gulf of Alaska. Surface geological parties increased 17% from 1965. The Gulf of Alaska and Arctic Slope were the most active basins. State competitive lease sales in the Cook Inlet basin and the Gulf of Alaska brought a total bonus of $7,177,160 for 152,577 acres. The Department of the Interior opened 4,000,000 acres on the Arctic Slope for simultaneous filing. Leasing was slowed by native land claims on approximately 60% of the land area of Alaska. Development drilling increased slightly; 9 oil wells were completed in offshore fields of Cook Inlet. Oil production increased 29% from 1965 to 14,358,212 bbls., and gas production increased 244% to 41,217,032 Mcf. In Cook Inlet 4 new drilling and production platforms were added to the 2 already in operation to drill the vast new offshore oil reserves. Five more platforms, to be erected in 1967, will provide a combined capacity of 400 wells. Dual pipelines 39 mi. long were laid to connect these new platforms to onshore facilities. Laying of a 20 in., 42-mi. pipeline began along the west shore of the Inlet, and will connect the developing west-side fields to a tanker terminal at Drift River. Ground was broken on the Kenai Peninsula near Nikiski for an ammonia-urea plant. The Kenai gas ield will provide the methane feedstock. The shut-in Beluga River gas field is expected to produce gas in 1967 to generate onsite electrical power for transmission to Anchorage.