Quantification of ash sedimentation dynamics through depolarisation imaging with AshCam

Area of Science:

• Volcanology
• Atmospheric Science
• Remote Sensing

Background:

• Volcanic ash clouds pose significant risks to air travel and human activities.
• Accurate quantification of ash aggregation and sedimentation in volcanic plumes is challenging.

Purpose of the Study:

• To develop and validate a new, cost-effective technique for imaging volcanic ash plume dynamics.
• To investigate ash aggregation and sedimentation processes using high-temporal-resolution data.

Main Methods:

• Imaging volcanic ash dynamics by measuring sunlight depolarization scattered by non-spherical ash particles.
• High-temporal-resolution imaging (>1 Hz) of diffuse ash plumes.
• Measuring ash settling velocity downwind and comparing with ground-sampled ash.

Main Results:

• Successfully imaged ash dynamics in diffuse plumes from Santiaguito Volcano, Guatemala.
• Measured ash settling velocities showed good agreement with a particle-size-based sedimentation model.
• Validated a new remote sensing technique for studying ash plume behavior.

Conclusions:

• The developed technique offers a new frontier for integrated ash visualization and ground collection studies.
• This method can test models of ash coagulation and sedimentation, improving dispersion forecasts.
• Enhanced data quality on ash location will aid risk managers and reduce socioeconomic impacts of eruptions.