@article{fdi:010086359,
  title = {{C}ollisional interactions and the transition between lava dome sector collapse and pyroclastic density currents at {T}utupaca volcano ({S}outhern {P}eru)},
  author = {{B}ernard, {K}. and {V}ries, {B}. {V}. {D}. and {S}amaniego, {P}ablo and {V}alderrama, {P}. and {M}arin, {J}.},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e describe sedimentological variations of the block-rich debris avalanche deposits and associated pyroclastic density current deposits emplaced around 1802 {CE} from {T}utupaca volcano in southern {P}eru. {W}e use these exceptionally well-preserved features to document the collisional shearing contact between the avalanche and coeval pyroclastic density currents. {F}urthermore, we show how the first stages of the edifice collapse and syn- cataclastic emplacement process affect the block-size distributions.{W}ith field observations, we describe imbricated block clusters, jigsaw cracks and striations related to elon-gated ridge structures on the deposit surface. {S}edimentological and statistical methods ({F}ourier {S}hape analysis and {S}hape {P}referred {O}rientation measured on 208 blocks and 566 mesoscale structures) help us to characterize the cataclastic gradient and establish the collisional relationships between different units. {W}e determine that the proximal impacted deposits and block lithofacies from ridges may be related to distal block units around-10 km run-out distance. {D}ifferent block clusters indicate a kinematic transition between avalanche units to pyroclastic density currents. {B}lock shape parameters help to differentiate rounded blocks resulting from matrix abrasion with and striated blocks from ridges related to proximal imbricated block clusters. {F}rom the statistical dataset, a few equations have been developed indicating a common cataclastic origin with a co-genetic evolution of block lithofacies during sequential syn-cataclastic emplacement.{T}he dome collapse is associated with a specific granular flow regime between avalanche and pyroclastic density currents with secondary reworking. {C}yclic impact waves contribute to block cluster growth. {C}lusters are disaggregated during shock propagation. {T}he inherited shapes of the block lithofacies with a/b = 1.2-2 and ellipse = 0.2-2.5 indicate the reworking by impact waves. {A} multidirectional switch to mass spreading in the median zone between 2 and 6 km may be considered with secondary flow and segregation waves. {A} basal frictional regime with striations is differentiated from collisional cataclastic flow, generating polymodal grooves during peak velocity at the flow front. {I}mpact forces around-15.7 x 1010 {N} are implied by suggested clast velocities around 8.86 m.s-1 and the transitional regime between avalanche units and pyroclastic density cur-rents between 15.5 and 39.6 m.s-1. {A}n extensional disaggregation with the fractal dimensions ({D}) of the sur-rounded matrix between 0.6 and 2.8 characterizes the granular transport. {A} collisional shearing contact probably operated between avalanche units and pyroclastic density currents, which contribute to co-genetic evolution of block clusters from median to frontal distal zones. {I}n the distal zone, abraded block clusters and tilted blocks are related to frontal reworking by impact wave.{T}he cataclastic gradient of avalanche units is correlated with the pyroclastic flow regime. {S}emi-quantitative analysis of block clusters provides information about syn-emplacement processes during sequential impact waves related to volcanic debris-avalanche units and pyroclastic density currents.},
  keywords = {{V}olcanic debris-avalanche deposit ; {L}ocal kinematics ; {B}lock clusters ; {S}triations ; {S}edimentology ; {PEROU} ; {TUTUPACA} {VOLCAN}},
  booktitle = {},
  journal = {{J}ournal of {V}olcanology and {G}eothermal {R}esearch},
  volume = {431},
  numero = {},
  pages = {107668 [15 ]},
  ISSN = {0377-0273},
  year = {2022},
  DOI = {10.1016/j.jvolgeores.2022.107668},
  URL = {https://www.documentation.ird.fr/hor/fdi:010086359},
}