@article{fdi:010044094,
  title = {{T}he {C}himborazo sector collapse and debris avalanche : deposit characteristics as evidence of emplacement mechanisms},
  author = {{B}ernard, {B}. and {V}ries de, {B}. {V}. and {B}arba, {D}. and {L}eyrit, {H}. and {R}obin, {C}laude and {A}lcaraz, {S}. and {S}amaniego, {P}ablo},
  editor = {},
  language = {{ENG}},
  abstract = {{C}himborazo is a {L}ate {P}leistocene to {H}olocene stratovolcano located at the southwest end of the main {E}cuadorian volcanic arc. {I}t experienced a large sector collapse and debris avalanche ({DA}) of the initial edifice ({CH}-1). {T}his left a 4 km wide scar, removing 8.0 +/- 0.5 km(3) of the edifice. {T}he debris avalanche deposit ({DAD}) is abundantly exposed throughout the {R}iobamba {B}asin to the {R}io {C}hambo, more than 35 km southeast of the volcano. {T}he {DAD} averages a thickness of 40 m, covers about 280 km(2), and has a volume of >11 km(3). {T}wo main {DAD} facies are recognized: block and mixed facies. {T}he block facies is derived predominantly from edifice lava and forms >80 vol.% of the {DAD}, with a probable volume increase of 15-25 vol.%. {T}he mixed facies was essentially created by mixing brecciated edifice rock with substratum and is found mainly in distal and marginal areas. {T}he {DAD} has clear surface ridges and hummocks, and internal structures such as jigsaw cracks, injections, and shear-zone features are widespread. {S}tructures such as stretched blocks along the base contact indicate high basal shear. {S}ubstratum incorporation is directly observed at the base and is inferred from the presence of substratum-derived material in the {DAD} body. {B}ased on the facies and structural interpretation, we propose an emplacement model of a lava-rich avalanche strongly cataclased before and/or during failure initiation. {T}he flow mobilises and incorporates significant substrata (10-14 vol.%) while developing a fine lubricating basal layer. {T}he substrata-dominated mixed facies is transported to the {DAD} interior and top in dykes invading previously-formed fractures.},
  keywords = {{C}himborazo ; {D}ebris avalanche deposit ; {B}lock facies ; {M}ixed facies ; {S}tructures ; {E}mplacement},
  booktitle = {},
  journal = {{J}ournal of {V}olcanology and {G}eothermal {R}esearch},
  volume = {176},
  numero = {1 {S}pecial {I}ssue},
  pages = {36--43},
  ISSN = {0377-0273},
  year = {2008},
  DOI = {10.1016/j.jvolgeores.2008.03.012},
  URL = {https://www.documentation.ird.fr/hor/fdi:010044094},
}