Finite-difference time-domain modeling of transient infrasonic wavefields excited by volcanic explosions

• Main Authors: Kim, K., Lees, J.M.
• Other Authors: College of Arts and Sciences, Department of Geological Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing Ltd 2011
• Subjects: Kamchatka; finite difference method; waveform analysis; wave field; geometry; Russian Federation; observational method; Karymsky Volcano; volcanic eruption; numerical model
• Online Access: https://doi.org/10.17615/p746-bh84; https://cdr.lib.unc.edu/downloads/ng451t456?file=thumbnail; https://cdr.lib.unc.edu/downloads/ng451t456

Numerical modeling of waveform diffractions along the rim of a volcano vent shows high correlation to observed explosion signals at Karymsky Volcano, Kamchatka, Russia. The finite difference modeling assumed a gaussian source time function and an axisymmetric geometry. A clear demonstration of the significant distortion of infrasonic wavefronts was caused by diffraction at the vent rim edge. Data collected at Karymsky in 1997 and 1998 were compared to synthetic waveforms and variations of vent geometry were determined via grid search. Karymsky exhibited a wide range of variation in infrasonic waveforms, well explained by the diffraction, and modeled as changing vent geometry. Rim diffraction of volcanic infrasound is shown to be significant and must be accounted for when interpreting source physics from acoustic observations.