TY - JOUR
T1 - Modeling the Dynamics of Dense Pyroclastic Flows on Venus
T2 - Insights Into Pyroclastic Eruptions
AU - Ganesh, Indujaa
AU - McGuire, Luke A.
AU - Carter, Lynn M.
N1 - Funding Information:
This study was supported by FINESST Grant 80NSSC19K1540 to I. Ganesh and SSW Grant 80NSSC20K1040 to L. M. Carter. The authors thank Eric Grosfils, two other anonymous reviewers, and the Editor‐in‐Chief Laurent Montési, for their constructive remarks.
Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.
PY - 2021/9
Y1 - 2021/9
N2 - On Venus, relatively young deposits near volcanic and coronal summits with unique radar characteristics have been proposed to be emplaced by pyroclastic density currents (PDCs). The proposed units are laterally extensive, long-runout deposits showing moderate to high radar backscatter and circular polarization ratio in 12.6 cm wavelength synthetic aperture radar data. Previous studies have hypothesized that a recent resumption of volcanic activity in the form of PDC-forming eruptions could have emplaced these deposits. We model the dynamics of dense PDCs using a 2D, depth-averaged framework focusing on regions where stereo-derived topography coverage is available; this includes the flanks of Irnini Mons, Anala Mons, Didilia Corona, and Pavlova Corona. Two different mechanisms of initiation which includes impulsive collapse of an eruption column and sustained pyroclastic fountaining are considered. The results emphasize the importance of pyroclastic flow fluidization via high pore pressure in emplacing long-runout deposits along gently sloping (<2°) volcanic flanks. We also show that collapse of columns >1.2–1.4 km tall as well as pyroclastic fountains lasting >400 s with fountain heights of 50 m are capable of generating pyroclastic flows that could emplace some of the smaller deposits studied. For the large deposits at Irnini Mons, more energetic flows resulting from taller column heights would be necessary; the dynamics of such flows under Venus's conditions are not well understood. Distinguishing between the two initiation styles, that is, column collapse and sustained fountaining is not feasible with currently available datasets and would require higher resolution imagery and topography data.
AB - On Venus, relatively young deposits near volcanic and coronal summits with unique radar characteristics have been proposed to be emplaced by pyroclastic density currents (PDCs). The proposed units are laterally extensive, long-runout deposits showing moderate to high radar backscatter and circular polarization ratio in 12.6 cm wavelength synthetic aperture radar data. Previous studies have hypothesized that a recent resumption of volcanic activity in the form of PDC-forming eruptions could have emplaced these deposits. We model the dynamics of dense PDCs using a 2D, depth-averaged framework focusing on regions where stereo-derived topography coverage is available; this includes the flanks of Irnini Mons, Anala Mons, Didilia Corona, and Pavlova Corona. Two different mechanisms of initiation which includes impulsive collapse of an eruption column and sustained pyroclastic fountaining are considered. The results emphasize the importance of pyroclastic flow fluidization via high pore pressure in emplacing long-runout deposits along gently sloping (<2°) volcanic flanks. We also show that collapse of columns >1.2–1.4 km tall as well as pyroclastic fountains lasting >400 s with fountain heights of 50 m are capable of generating pyroclastic flows that could emplace some of the smaller deposits studied. For the large deposits at Irnini Mons, more energetic flows resulting from taller column heights would be necessary; the dynamics of such flows under Venus's conditions are not well understood. Distinguishing between the two initiation styles, that is, column collapse and sustained fountaining is not feasible with currently available datasets and would require higher resolution imagery and topography data.
KW - 2D mass flow model
KW - Magellan SAR
KW - Venus
KW - explosive volcanism
KW - pyroclastic flows
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U2 - 10.1029/2021JE006943
DO - 10.1029/2021JE006943
M3 - Article
AN - SCOPUS:85115694524
VL - 126
JO - Journal of Geophysical Research: Planets
JF - Journal of Geophysical Research: Planets
SN - 2169-9097
IS - 9
M1 - e2021JE006943
ER -