Satellites usually work alone, mainly they send data back to Earth from the source satellite and that data are then processed before being distributed or placed in a repository. This not only takes some time but often is only one level of data. Monitoring earthquakes and volcanic eruptions present scientists with a relatively fast-moving geological event that has to be captured at the right moment for data to be relevant. Furthermore, such events could be affected by changes to the Earth’s crust that occur both near and far from an area affected by seismic changes. The development of new satellites to monitor reseismic change not only helps to create new opportunities for seismic monitoring but such satellite technologies also benefit Earth observation more broadly.
One relatively new satellite is a small satellite system called the CubeSat Imaging Radar for Earth Sciences (CIRES). This satellite system, which can work as a group of small satellites, is equipped with S-band Interferometric Synthetic Aperture Radar (InSAR), a form of radar that can penetrate vegetation and other above ground interference. The CIRES satellite is able to pass the same point roughly twice in a given time interval and then it makes measurements using the radar to determine changes in elevation. Sudden changes can help detect potential volcanic and seismic activity in the area. What is also new about such satellites is they can be programmed to work in tandem with larger satellites that consistently orbit the Earth but capture more macro-level data. Data from CIRES satellites, including a cluster of them, can send information to such satellites as NASA’s ISRO SAR Mission (NISAR), which is a larger radar satellite that has different levels of global data including elevation. The frequency of changes and differences measured across small and larger scales, such as volcanoes inflating before an eruption in a local areas also causing seismic change in more distant areas, could enable satellites to determine or at least send data that suggests volcanic activity is likely in a given location.
The advantage of CIRES satellites is they can work either together or alone, while also being ideal to monitoring relatively fast moving geological change using radar. One of the key technologies on such satellites is SpaceFibre, which is a type of protocol used for data transmission from satellites. The ability to make these transmission services powerful enables smaller satellites like CubeSats, which can weigh about 1 kg, to carry such technologies that can handle large data volumes that derive from synthetic aperture radar (SAR) readings, which were previously only transmitted from much larger satellite systems or even the space shuttle.
In general, NASA has seen that smaller satellites that are cheaper and better able to work with other satellites and ground-based systems as a potentially better future for Earth observation. The CIRES program was developed by the Jet Propulsion Laboratory (JPG) and SRI International, with funding coming from NASA’s Earth Science Technology Office (ESTO). Other areas within observation may soon benefit from similar developments that have made geological observation, particularly seismic events, easier. This includes improvements in measures for altimetry, sounding, scatterometry, and precipitation profiling. This could mean the use of similar CubeSats that work in tandem with large satellite systems relevant for vegetation, weather, and other forms of fast-moving geological observations and change. Furthermore, CubeSats could be put together into a larger satellite system, given their compact cubic design that is standardized and made for them to be self-sustaining but also attachable to a larger chassis.
Changes to geological observation in the last year have meant now it is possible to observe key metrics for volcanic eruptions and even earthquakes before seismic events happen. This could portend well for forecasting these events in the future. In particular, traditional ground-based observation has not been sufficient to enable forecasts to be precise for seismic events. However, combining macro-level Earth observation along with small-scale observation of local areas using CubeSats and radar technologies could mean improved forecasting capabilities. For now, geologists are only beginning to get use to the new data available to them so we will have to wait and see how new systems like CIRES could improve our understanding of fast-moving geological events. From initial observations, the future does look promising.
References For more on the use of CIRES and NISAR satellites in monitoring seismic and volcanic changes, see: https://www.nasa.gov/feature/goddard/2020/new-nasa-radar-looks-to-monitor-volcanoes-and-earthquakes-from-space  For more on how data protocols are used to transmit information from CubeSats, see: Dinelli G, Nannipieri P, Davalle D, et al. (2019) Design of a Reduced SpaceFibre Interface: An Enabling Technology for Low-Cost Spacecraft High-Speed Data-Handling. Aerospace 6(9): 101. DOI: 10.3390/aerospace6090101.  For a review and more on the components and developments in CubeSats that makes them useful for potentially other forms of Earth observation, see: Peral E, Im E, Wye L, et al. (2018) Radar Technologies for Earth Remote Sensing From CubeSat Platforms. Proceedings of the IEEE 106(3): 404–418. DOI: 10.1109/JPROC.2018.2793179.