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Lahars 13 March 2019. Vallance and Iverson, EOV2, 2015. this is the flow. this is the deposit. bulking. Downstream transformations of a lahar. Vallance and Iverson, EOV2, 2015. Mt. St. Helens – pumiceous pyroclastic flow from 1980. Lahars – effects on river systems and deposits.
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Lahars 13 March 2019
Vallance and Iverson, EOV2, 2015 this is the flow this is the deposit
bulking Downstream transformations of a lahar Vallance and Iverson, EOV2, 2015
Lahars at Armero following the eruption of Nevado del Ruiz, 13 November 1985 Mountain front Partial inundation No inundation Total inundation
Lahars filling rivers following the 18 May 1980 eruption of Mount St. Helens
Lahar-inundated communities following the 15 June 1991 eruption of Mt. Pinatubo, Philippines
Breaching of levees by lahars filling river drainages after the Pinatubo eruption
debris flow hyperconc. flow debris flow Above - Debris flow (unstratified) and hyperconcentrated flow (stratified) deposits, east side Mt. Pinatubo Pumice-rich debris flow deposit, east side Mt. Pinatubo, 20-21 Aug 1991 Lake breakout deposits, east side Mt. Pinatubo
Rapid erosion of lahar deposits following the 18 May 1980 Mt. St. Helens eruption
Comparison of air photos taken in June 1978 and June 1980 of the North Fork of the Toutle River near Mt. St. Helens
Maximum inundation levels by lahars following the 18 May 1980 eruption of Mt. St. Helens
Lahar inundations and mud-coated debris after the Mt. St. Helens eruption
Normally graded Osceola Mudflow lahar deposit, Mt. Rainier (Vallance and Scott 1997)
Hummocky Osceola Mudflow deposit, Mt. Rainier (Vallance and Scott 1997)
Mobility of debris avalanches vs. debris flows (from Vallance and Scott 1997) Vallance and Iverson, EOV2, 2015 H = fall height L = runout
Chillos Valley lahar, Cotopaxi, Ecuador (Mothes et al 1998) ~4.5 ka, ~3.8 km3 Note the matrix-supported and ungraded lahar deposit
Comparison of lahar travel distances: Cotopaxi, Mt. St. Helens, Nevado del Ruiz south north
Grain size parameters as a function of distance from the source Chillos Valley lahar Osceola Mudflow