@article{fdi:010057343,
  title = {{L}i{DAR} derived morphology of the 1993 {L}ascar pyroclastic flow deposits, and implication for flow dynamics and theology},
  author = {{J}essop, {D}. {E}. and {K}elfoun, {K}arim and {L}abazuy, {P}. and {M}angeney, {A}. and {R}oche, {O}livier and {T}illier, {J}. {L}. and {T}rouillet, {M}. and {T}hibault, {G}.},
  editor = {},
  language = {{ENG}},
  abstract = {{P}umice flows are potentially destructive volcanic events that derive from eruption column collapse and whose dynamics are poorly understood. {T}he challenges in studying these flows include the lack of constraints on the dynamics, kinematics and initial conditions that control their emplacement. {W}e present a morphological study of the distal deposits (lobes) of the pumice flows resulting from the 1993 eruption at {L}ascar, {C}hile. {T}he surface geometry of the lobes was measured in detail using a {L}i{DAR} device, which allowed for detailed characterisation of their morphology, consisting of central channel and lateral levees, and terminal frontal snout. {I}n particular we find that the ratio of channel/levee height as a function of the ratio of the distance between levees/total width of the lobe has a characteristic curve for these pumice flow lobes. {O}ur analysis of several of the {L}ascar pumice lobe deposits (south east sector) identified several dimensionless groups of the available parameters which, when compared against published results from both experimental and numerical investigations, allowed us to constrain crucial kinematic and dynamic information on the terminal phase of the pumice flows. {N}otably, we estimate the velocity of the terminal phase of pumice flows to be 5-10 m/s. {F}roude numbers of 1.5-2 are comparable with values found for experimental granular flows. {H}eight-width aspect ratios for the levee-channel section of the pumice lobes are similar to those for experimental flows although these same aspect ratios for the snout are much larger for the natural deposits than their small-scale analogues. {F}inally, we discuss the possible emplacement dynamics of the terminal {L}ascar 1993 pumice flows. {A} pseudo-{R}eynolds number based on the velocity estimation is found to be up to 100 times larger for the pumice flows than experimental-scale flows. {T}his suggests that the flow-retarding frictional forces for large-scale flows are relatively unimportant compared to flows at smaller scales. {M}echanical effects such as fluidisation, mobilisation of material lying on the slopes over which they propagate and lubrication due to polydispersivity could provide an explanation for their ability to propagate on shallow slopes (6-11 degrees).},
  keywords = {{P}umice flow deposits ; {L}ascar ; {M}orphology ; {D}ynamics ; {K}inematics ; {V}elocity ; {L}i{DAR}},
  booktitle = {},
  journal = {{J}ournal of {V}olcanology and {G}eothermal {R}esearch},
  volume = {245},
  numero = {},
  pages = {81--97},
  ISSN = {0377-0273},
  year = {2012},
  DOI = {10.1016/j.jvolgeores.2012.06.030},
  URL = {https://www.documentation.ird.fr/hor/fdi:010057343},
}