281 Petrology, Volcanology, and Mantle Plumes across the Solar System, Part II

This session focuses on recent advances in characterizing and quantifying volcanic processes throughout the Solar System in light of recent and upcoming missions to volcanically active worlds and resurgence in volcano science.

Wednesday, 22 October 2025
1:30 PM - 5:30 PM
HBGCC, 214C

Searching for Young Lavas on Venus Using Magellan Microwave Radiometry

Paper number: 281-2
Program: Technical Sessions
Time: 1:55 PM – 2:10 PM

Authors

Abstract

Despite studies that suggest that Venus is volcanically active, unambiguous identification of active volcanoes on the planet remains a challenge. Proposed and implemented approaches to detecting volcanic activity focus on repeated radar imaging to identify surface changes, elevated infrared (IR) emissions associated with unweathered lavas or surface temperature anomalies, and elevated microwave radiometry emissions linked to subsurface thermal anomalies. Arguably, the least understood of these approaches is the use of microwave radiometry for identifying recent volcanic flows. Orbital microwave radiometers, like those onboard missions such as Magellan and EnVision, record emission at microwave wavelengths from the shallow subsurface. In theory, this technique enables detection of actively cooling lava flows which tend to retain heat in the interior even after the surface has cooled to ambient temperatures. Analysis of radiometry data for Earth, however, has demonstrated that detecting young lava flows with high dielectric loss and small spatial extent relative to the instrument footprint is difficult (MacKenzie and Lorenz, 2020). In view of this known challenge, can we effectively identify sites of recent effusive activity on Venus using orbital microwave radiometry? To answer this question, we undertake a global survey of Magellan radiometry observations to identify regions exhibiting elevated microwave emission, and use 1D models of microwave emission from cooling lava flows to determine the range of subsurface temperatures and material dielectric properties that can increase emission to observed values. Preliminary results from our survey indicate that a variety of terrain types including lava flows (e.g. flows from Maat Mons, Ozza Mons, and Kali Mons), volcanic fields (e.g. the Aurelia crater volcanic shield field), and low-backscatter deposits near volcanic centers (e.g. summit deposits at Anala and Gula Montes) exhibit elevated microwave emission. Further analysis of Magellan radar data is required to determine if these observed increases in microwave emission are related to subsurface temperature excess or only to surface roughness and/or dielectric properties. Future NIR and radiometry observations of these sites will allow better understanding of the thermal evolution of Venusian lavas and current rates of effusive volcanic activity. 

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412445

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