Innovative solid Earth applications of future gravity field missions

The upcoming gravity missions anticipated in the next decade are expected to significantly reduce noise levels compared to current data acquisitions from GRACE and GRACE Follow On. Our objective is to proactively prepare for these future datasets and develop scientific processing tools that can yield innovative applications in solid earth research. These applications have the potential to evolve into community-relevant ser-vices for earth monitoring and exploration.

We specifically focus on key categories such as earthquakes, crustal uplift and subsidence, seamounts, and lithospheric structure. Accurately estimating the gravity field necessitates the formulation of realistic 3D models of density and their temporal changes.

Uplift and subsidence is considered for the Alpine mountain arc, where a lithosphere density model has been formulated (Tadiello & Braitenberg, 2021) imposing vertical movements from measured GNSS rates. The exploration of the lithosphere is tested on a recent 3D density model of Iran (Maurizio et al., 2023) which was inverted from the presently available gravity field integrated with a seismic tomography model. We distinguish crustal and mantle signals and evaluate prospective improvements to detect structures in crust and mantle.

In the context of earthquakes, our focus lies in improving the minimum detectable magnitude, depending on fault plane mechanisms, and detecting post-seismic relaxation. Seamounts pose a unique challenge with limited alternatives for detection, placing gravity detection in a primary role, provided the associated mass changes are sufficiently significant. Therefore, we conduct a review of documented seamount eruptions, estimating the associated mass changes. Particularly intriguing are 'silent' seamounts that grow several hundred meters high without breaking the ocean surface, remaining invisible.

We compare the signals against noise levels of the future gravity missions, including the polar and inclined satellite couples with inter satellite distance measurement, the MAGIC proposal (Daras et al., 2024) and proposals with the payload of quantum technology gradiometers presently under discussion at ESA and NASA.

 

References

Daras, I., March, G., Pail, R., Hughes, C. W., Braitenberg, C., Güntner, A., Eicker, A., Wouters, B., Heller-Kaikov, B., Pivetta, T., & Pastorutti, A. (2024). Mass-change And Geosciences International Constellation (MAGIC) expected impact on science and applications. Geophysical Journal International, 236(3), 1288–1308. https://doi.org/10.1093/gji/ggad472

Maurizio, G., Braitenberg, C., Sampietro, D., & Capponi, M. (2023). A New Lithospheric Density and Magnetic Susceptibility Model of Iran, Starting From High‐Resolution Seismic Tomography. Journal of Geophysical Research: Solid Earth, 128(12), e2023JB027383. https://doi.org/10.1029/2023JB027383

Tadiello, D., & Braitenberg, C. (2021). Gravity modeling of the Alpine lithosphere affected by magmatism based on seismic tomography. Solid Earth, 12(2), 539–561. https://doi.org/10.5194/se-12-539-2021