Contrasting origin of two clay-rich debris flows at Cayambe Volcanic Complex, Ecuador

Detienne, Marie; Delmelle, Pierre; Guevara, Alicia; Samaniego, Pablo; Opfergelt, Sophie; Mothes, Patricia

doi:10.1007/s00445-017-1111-2

Cited by 11 publications

(14 citation statements)

References 33 publications

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“…Cronin et al ., ; Detienne et al ., ). It is important to identify hydrothermal minerals formed under near surface, supergene or hypogene hydrothermal environments (John et al ., ; Detienne et al ., ), as well as sulphidation states such as high sulphidation in the central part of a volcano or low sulphidation more distally (Hedenquist & Lowenstern, ), and whether they are linked to vertical and lateral distributions sampled by: (i) a surface landslide; (ii) a deeper collapse; and/or (iii) a phreatic (hydrothermal) eruption without collapses (John et al ., ; Sillitoe, ; Detienne et al ., ). The XRD results (Table ) indicate that the both Gm/Gs and Bm/Bs deposits have a variety of clay mineralogy derived from hydrothermally altered rocks (details discussed below) suggesting a different source.…”

Section: Eruptive Styles and Lahar Trigger Revealed By Event Depositsmentioning

confidence: 97%

From sink to volcanic source: Unravelling missing terrestrial eruption records by characterization and high‐resolution chronology of lacustrine volcanic density flow deposits, Lake Inawashiro‐ko, Fukushima, Japan

Kataoka

Nagahashi

2019

Sedimentology

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Eruption records in the terrestrial stratigraphy are often incomplete due to erosion after tephra deposition, limited exposure and lack of precise dating owing to discontinuity of strata. A lake system and sequence adjacent to active volcanoes can record various volcanic events such as explosive eruptions and subaqueous density flows being extensions of eruption triggered and secondary triggered lahars. A lacustrine environment can constrain precise ages of such events because of constant and continuous background sedimentation. A total of 71 subaqueous density flow deposits in a 28 m long core from Lake Inawashiro-ko reveals missing terrestrial volcanic activity at Adatara and Bandai volcanoes during the past 50 kyr. Sedimentary facies, colour, grain size, petrography, clay mineralogy, micro X-ray fluorescence analysis and chemistry of included glass shards characterize the flow event deposits and clarify their origin: (i) clay-rich grey hyperpycnites, extended from subaerial cohesive lahars at Adatara volcano, with sulphide/sulphate minerals and high sulphur content which point to a source from hydrothermally altered material ejected by phreatic eruptions; and (ii) clay-rich brown density flow deposits, induced by magmatic hydrothermal eruptions and associated edifice collapse at Bandai volcano, with the common presence of fresh juvenile glass shards and low-grade hydrothermally altered minerals; whereas (iii) non-volcanic turbidites are limited to the oldest large slope failure and the 2011 Tohoku-oki earthquake events. The high-resolution chronology of volcanic activity during the last 50 kyr expressed by lacustrine event deposits shows that phreatic eruption frequency at Adatara has roughly tripled and explosive eruptions at Bandai have increased by ca 50%. These results challenge hikers, ski-fields and downstream communities to re-evaluate the increased volcanic risks from more frequent eruptions and far-reaching lahars, and demonstrate the utility of lahar and lacustrine volcanic density flow deposits to unravel missing terrestrial eruption records, otherwise the recurrence rate may be underestimated at many volcanoes.

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Section: Eruptive Styles and Lahar Trigger Revealed By Event Depositsmentioning

confidence: 97%

From sink to volcanic source: Unravelling missing terrestrial eruption records by characterization and high‐resolution chronology of lacustrine volcanic density flow deposits, Lake Inawashiro‐ko, Fukushima, Japan

Kataoka

Nagahashi

2019

Sedimentology

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“…3a). This escarpment resulted from a sector collapse most likely caused by hydrothermal alteration that weakened the western flank of Nevado Cayambe edifice during the Late Pleistocene (Detienne et al, 2017). As a result of this event, the steep slopes of the upper Río Blanco valley are characterized by a widespread hydrothermal alteration.…”

Section: Río Blanco Longitudinal Profile (A-a') -East To Westmentioning

confidence: 99%

Evidence of destructive debris flows at (pre-) Hispanic Cayambe settlements, Ecuador

Vasconez

Samaniego

Phillips³

et al. 2023

Preprint

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<p>In Ecuador, a country with numerous potentially active volcanoes, recurrent large earthquakes, and regular climate-related events, it is surmised that phenomena such as debris flows have affected pre-Hispanic populations since their settlement in ~5000 cal BC. Here, using a multidisciplinary approach, we studied the most recent debris flow events that affected the Cayambe city area, located 15 km west of the active glacier-clad Cayambe volcano. Based on detailed characterization of the deposits, including sedimentological, archaeological, and paleontological analyses, as well as radiocarbon dating. We found that two debris flow (i.e., R&#237;o Blanco I and II) destroyed Caranqui settlements in 665&#8211;775 cal AD and 774&#8211;892 cal AD, respectively, while another event impacted a Spanish colonial farm in 1590 &#8211;1620 cal AD (R&#237;o Blanco III). The grain size distribution of these deposits indicates a gravel-rich flow for R&#237;o Blanco I and clay-rich flow for R&#237;o Blanco II and III, whilst componentry suggests low juvenile volcanic content for all three deposits. Juvenile components include pumice and lustrous dense dacites, while accidental clasts are dull dense dacites, oxidized and hydrothermally-altered material, as well as archaeological artifacts. These results, in addition to radiocarbon ages, suggest that the debris flows could either be post-eruptive or not related to volcanic eruptions. Potential non-volcanic trigger mechanisms for these events include rainfall and/or earthquakes, which implies that they can occur at any time and without forecast. Currently, the city of Cayambe is rapidly expanding and, consequently, our findings are relevant for creating impact scenarios for future debris flows forming in the Rio Blanco headwaters and descending to the city.</p>

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“…This study focuses on Cayambe Volcano, in the north of the Eastern Cordillera of the Ecuadorian Andes, just 60 km north of the capital Quito. The complex is a notably large volcanic centre, with a peak elevation of 5,790 m. Above 4,800 m the volcano is covered in a 22 km 2 ice cap, which in places is as thick as 100 m (Guillier and Chatelain, 2006;Detienne et al, 2017). Tephrochronology studies have revealed previous explosive activity in the last 4,000 years, including pyroclastic flows, lava dome extrusions and collapse events (Samaniego et al, 1998).…”

Section: Cayambe Volcanomentioning

confidence: 99%

“…Hydrothermal alteration of flank deposits and thawing soils from glacial retreat act to destabilise the western slopes of Cayambe. Small perturbations in the system, for example, from a magmatic intrusion or seismic event, could lead to catastrophic failure and significant landslides (Hoblitt et al, 1998;Detienne et al, 2017). This would pose a threat to the town of Cayambe, population 20,000, that sits just 15 km west of the volcano (Samaniego et al, 1998).…”

Section: Cayambe Volcanomentioning

confidence: 99%

Evolution of Seismicity During a Stalled Episode of Reawakening at Cayambe Volcano, Ecuador

et al. 2021

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Cayambe Volcano is an ice-capped, 5,790 m high, andesitic-dacitic volcanic complex, located on the equator in the Eastern Cordillera of the Ecuadorian Andes. An eruption at Cayambe would pose considerable hazards to surrounding communities and a nationally significant agricultural industry. Although the only historically documented eruption was in 1785, it remains persistently restless and long-period (LP) seismicity has been consistently observed at the volcano for over 10 years. However, the sparse monitoring network, and complex interactions between the magmatic, hydrothermal, glacial, and tectonic systems, make unrest at Cayambe challenging to interpret. In June 2016 a seismic “crisis” began at Cayambe, as rates of high frequency volcano-tectonic (VT) earthquakes increased to hundreds of events per day, leading to speculation about the possibility of a forthcoming eruption. The crisis began 2 months after the Mw7.8 Pedernales earthquake, which occurred on the coast, 200 km from Cayambe. Here we show that the 2016 seismicity at Cayambe resulted from four distinct source processes. Cross correlation, template matching, and spectral analysis isolate two source regions for VT earthquakes–tectonic events from a regional fault system and more varied VTs from beneath the volcanic cone. The temporal evolution of the LP seismicity, and mean Q value of 9.9, indicate that these events are most likely generated by flow of hydrothermal fluids. These observations are consistent with a model where a new pulse of magma ascent initially stresses regional tectonic faults, and subsequently drives elevated VT seismicity in the edifice. We draw comparisons from models of volcano-tectonic interactions, and speculate that static stress changes from the Pedernales earthquake put Cayambe volcano in an area of dilation, providing a mechanism for magma ascent. Our findings provide a better understanding of “background” seismicity at Cayambe allowing faster characterization of future crises, and a benchmark to measure changes driven by rapid glacial retreat.

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Contrasting origin of two clay-rich debris flows at Cayambe Volcanic Complex, Ecuador

Abstract: International audienc

Cited by 11 publications

References 33 publications

From sink to volcanic source: Unravelling missing terrestrial eruption records by characterization and high‐resolution chronology of lacustrine volcanic density flow deposits, Lake Inawashiro‐ko, Fukushima, Japan

From sink to volcanic source: Unravelling missing terrestrial eruption records by characterization and high‐resolution chronology of lacustrine volcanic density flow deposits, Lake Inawashiro‐ko, Fukushima, Japan

Evidence of destructive debris flows at (pre-) Hispanic Cayambe settlements, Ecuador

Evolution of Seismicity During a Stalled Episode of Reawakening at Cayambe Volcano, Ecuador

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