InSight Lessons on Science Potential From On-Deck Operation of a Broadband Seismometer

Date: 4/25/2019

Time: 06:00 PM

Room: Fifth Avenue

The InSight mission to Mars is now returning seismic data from another planetary body for the first time since Apollo lunar data and Viking Mars data from the 1970’s. Part of the reason for the lack of planetary seismic deployments is a perceived complexity of seismic instrumentation in order to have extremely sensitive instruments well-coupled with ground motion. A large reason for this is the lack of clear identification of Marsquakes in the Viking data, and the final report of the Viking seismology project, which identified direct coupling to the ground as an important future consideration to move beyond the Viking seismometer. However, there were other features of the Viking seismology project that hampered its ability to detect internal events, primarily the relatively low sensitivity of the instrument strongly peaked near a resonant frequency of 3 Hz, and much of the data was sent back in a compressed event mode consisting of an envelope amplitude sent back at approximately 1 Hz and a count of positive-going zero crossings.

Given the deployment complexity of surface instrument placement, though, it’s important to better constrain the science potential of modern seismometers mounted on a spacecraft. While InSight has now deployed its seismic instrument package (Seismic Experiment for Internal Stucture, or SEIS) on the surface, the short period instrument (SP) successfully operated on the deck. Temperature limitations and other operational concerns prevented continuous operation, but over 47 hours of data were recorded over a 3-week period on the deck. While this data does not cover all portions of the diurnal cycle, it includes periods both before and after sunset and covering a range of atmospheric noise conditions. This dataset is powerful for understanding the noise characteristics of deck-deployed seismometers and can be used to better understand the science potential of future seismic deployments on landed assets on Mars and other planetary bodies, including for airless bodies when the calmest periods recorded by InSight are considered.

Presenting Author: Mark P. Panning

Authors