Catastrophic debris avalanche from ancestral Mount Shasta volcano, California

Crandell, Dwight Raymond; Miller, C. Dan; Glicken, Harry; Christiansen, Robert L.; Newhall, Christopher G.

doi:10.1130/0091-7613(1984)12<143:cdafam>2.0.co;2

Cited by 185 publications

(77 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We use the term matrix facies for that unconsolidated part of the avalanche deposit in which original constituents have been completely mingled, e.g. completely disaggregated source material and entrained loose debris, conceivably containing most types of rock from the source area (Glicken 1998;Ui & Glicken 1986;Crandell et al 1984;Ui et al 2000). Fragments in both of these end-member facies typically are angular, and form unstratified, poorly sorted breccias and gravels.…”

Section: Debris Avalanche Textural Facies and Map Unitsmentioning

confidence: 99%

The 26 December (Boxing Day) 1997 sector collapse and debris avalanche at Soufrière Hills Volcano, Montserrat

Voight

Komorowski²,

Norton

et al. 2002

Memoirs

102

View full text Add to dashboard Cite

Abstract:The southern sector of Soufriere Hills Volcano failed on 26 December 1997 (Boxing Day), after a year of disturbance culminating in a devastating eruptive episode. Sector collapse produced a c. 50 x l0 6 m 3 volcanic debris avalanche, and depressurized the interior of the lava dome, which exploded to generate a violent pyroclaslic density current. The south-directed growth of a lava lobe and build-up of lava-block talus, since early November 1997. brought the hydrothermally weakened sector to a condition of marginal stability. Limit-equilibrium stability analyses and finite-difference stress-deformation analyses, constrained by geomechanical testing of edifice and debris avalanche materials, suggest that the sector collapse was triggered by a pulse of co-seismic exogenous lava shear-lobe emplacement. Slip-surface localization was influenced by strain-weakening.The source region fragmented into avalanche megablocks, and further disruption generated a chaotic avalanche mixture that included variably indurated and coloured hydrothermally altered material, and much talus. The avalanche consisted of several flow pulses that reflected complexities of source disruption and channel topography. In the proximal zone, within 1.5 km from source, many megablocks preserve pre-collapse stratigraphy. At major bends the avalanche separated into channelled and overspill flows. In the distal region, >2.5 km from source, stacked sets of the main lithologies occur with a hummocky surface and abrupt flowage snouts, beyond which sparse hummocks occur in a thinly spread deposit. Textures suggest emplacement by laminar mass transport of partly saturated debris riding on a frictionally sheared base. Three-dimensional numerical simulations of emplacement governed by a Coulomb-type (Pouliquen) basal friction law imply low values of friction (< 15 o ), consistent with geotechnical test data and the localized presence of pore-water pressures. The best-fit model suggests an emplacement time <3 minutes and a typical maximum velocity of about 40 ms -1 , which are consistent with field estimates.Following over a year of disturbance, the southern flank of Soufriere Hills Volcano failed on 26 December (Boxing Day) 1997, generating the most devastating episode of the entire eruption . The complex series of events resembles, on a smaller scale, the debris avalanche and directed blast that occurred at Mount St Helens in 1980 (Lipman & Mullineaux 1981. At Soufriere Hills, an andesilic lava dome had grown over the unstable, hydrothermally weakened southern sector of the edifice. When this sector collapsed on Boxing Day, the interior of the lava dome was exposed and depressurized, and it exploded to generate a powerful pyroclastic density current that ravaged the southwestern flank and entered the sea. This paper focuses on the mechanics of the sector collapse and on the emplacement dynamics, characteristics and properties of the deposit of the resulting debris avalanche (Fig. I). It is based primarily on fieldwork conducted at various times i...

show abstract

Section: Debris Avalanche Textural Facies and Map Unitsmentioning

confidence: 99%

The 26 December (Boxing Day) 1997 sector collapse and debris avalanche at Soufrière Hills Volcano, Montserrat

Voight

Komorowski²,

Norton

et al. 2002

Memoirs

102

View full text Add to dashboard Cite

show abstract

“…The area of a deposit where FRCs are predominant, and where a hummocky surface develops, was mapped as an axial facies by Neall (1979) and as a block facies by Crandell et al (1984). In contrast, the area where inter-clast matrix is predominant was mapped as marginal facies by Neall (1979), as matrix facies by Crandell et al (1984), as main facies by Mimura & Kawachi (1981), and matrix mixture by Ui (1983).…”

Section: Nomenclature and Facies Architecturementioning

confidence: 99%

“…In contrast, the area where inter-clast matrix is predominant was mapped as marginal facies by Neall (1979), as matrix facies by Crandell et al (1984), as main facies by Mimura & Kawachi (1981), and matrix mixture by Ui (1983).…”

Section: Nomenclature and Facies Architecturementioning

confidence: 99%

“…Then in 1975, Ando & Yamagishi (1975) concluded that many of the mudflow hills at the base of Japanese volcanoes actually formed by either cold or hot avalanches. The 1980 Mt St Helens eruption was the first instance in which details of a large volcanic debris-avalanche were observed and documented at the time of emplacement (e.g., Glicken et al 1981;Voight et al 1981Voight et al , 1983Glicken 1986) and this event has provided a pivotal model for the interpretation of similar deposits elsewhere (e.g., Soya & Katsui 1981;Mimura et al 1982;Crandell et al 1984).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stratigraphy, age, and correlation of voluminous debris‐avalanche events from an ancestral Egmont Volcano: Implications for coastal plain construction and regional hazard assessment

Alloway

McComb²,

Neall

et al. 2005

Journal of the Royal Society of New Zealand

View full text Add to dashboard Cite

“…Some well-known examples include the debris-avalanche deposit at Mt. Shasta (Crandell et al, 1984), and the debris-avalanche deposits at Bandai and Unzen Volcanoes (Siebert et al, 1987). The sedimentological characteristics of debris-avalanche deposits are described in Ui (1983) and Ui et al (1986).…”

Section: Debris Avalanche Motionmentioning

confidence: 99%

Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska

Waythomas

Watts²,

Walder

2006

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

Catastrophic debris avalanche from ancestral Mount Shasta volcano, California

Cited by 185 publications

References 3 publications

The 26 December (Boxing Day) 1997 sector collapse and debris avalanche at Soufrière Hills Volcano, Montserrat

The 26 December (Boxing Day) 1997 sector collapse and debris avalanche at Soufrière Hills Volcano, Montserrat

Stratigraphy, age, and correlation of voluminous debris‐avalanche events from an ancestral Egmont Volcano: Implications for coastal plain construction and regional hazard assessment

Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska

Contact Info

Product

Resources

About