PROJECT: GRC: The Alaska–Venus analog: synthesizing seismic ground motion and wind noise in extreme environments
Science PI: Il-Sang Ahn, Assistant Professor, UAF
Due to the similarity in size and overall surface age between the two planets, Earth and Venus are referred to as twins. Despite these similarities, Venus seems to have a different interior structure and has clearly experienced a different surface evolution. The Magellan mission to Venus revealed that the planet’s surface does not exhibit plate tectonics, notwithstanding evidence of crustal movement and surface deformation. To understand the origins of these differences, we turn to seismology, a preeminent geophysical tool for understanding tectonic activity and the interior structure of a planet. However, the major challenge for a seismometer deployed on the Venusian surface is the extreme environment: its temperatures reach 460°C, its pressure can be over 90 bar, and its reactive atmospheric chemistry is primarily composed of supercritical CO2 with sulfur species and other reactive elements.
Advances in the technology of high-temperature electronics, led by research conducted at the NASA Glenn Research Center (GRC), are expected to make it possible to deploy a seismometer on the surface of Venus within the next decade. A battery-powered Venus seismometer could monitor seismic events for 120 Earth days. However, due to power constraints, less than ten hours of data could be transmitted to an orbiter over the mission period. Consequently, the onboard seismometer should be equipped with intelligent operation strategies that distinguish seismic signal from noise, which requires thorough and accurate prediction of Venusian seismograms. University of Alaska (UA) faculty on the proposing team have conducted initial research on this topic under a partnership with GRC, and these initial efforts have revealed significant gaps in knowledge that we aim to fill with the proposed work.
Our overall goal for this project is to develop and assess Venus seismometer operation strategies, based on what a deployed Venus seismometer will observe. This research will use synthetic seismograms generated by combining synthetic Venus ground motions with synthetic Venusian surface wind waveforms. First, we will synthesize realistic ground motions for Venus based on our current understanding of the Venusian interior and various hypothesized geodynamic states. Second, we will create a realistic model of wind noise on Venus; wind is expected to be the primary source of seismic noise, and presents a modeling challenge due to extreme atmospheric conditions on Venus with respect to Earth. Third, we will measure seismograms at Venus-analog sites in Alaska and Hawaii to develop, test, and validate our modeling work. Finally, we will use our cumulative knowledge to develop effective Venus seismometer operation strategies under the constraints given by expected instrument capabilities and possible mission plans.
The proposed work will significantly benefit future Venus missions deploying seismometers on the surface or using other techniques such as infrasound to explore Venus seismicity. The resulting tools developed in this work will also enhance the ability of seismologists and earthquake engineers in the Alaska EPSCoR jurisdiction to understand Alaska’s subsurface and near-surface. This also presents an opportunity to develop and reinforce partnerships between engineering efforts at UA Anchorage and UA Fairbanks that focus on mitigating seismic hazards in manmade structures, as well as research seismologists at the Geophysical Institute, UA Fairbanks, and engineers at GRC.