129 Deep Lunar interior seismic inversion with FSS, CH7 and Apollo

Job title:

129 Deep Lunar interior seismic inversion with FSS, CH7 and Apollo

Company:

Centre National d’Etudes Spatiales

Job description

The FarSide Seismic Suite (FSS) is set to launch the most sensitive planetary sensor, the Very Broad Band Vertical (VBBZ) seismometer to the Moon in the summer of 2026. This groundbreaking instrument will be deployed in the Schrodinger Basin on the Moon’s far side with a nominal 4.5 months duration mission likely extended by one year . Following this, the ChangE’7 mission will deploy a lunar seismometer (LS) near the Shackleton Crater, close to the lunar South Pole and also planned for operations of a few years.These two seismic stations will revitalize lunar seismic monitoring after nearly 50 years, filling the gap left since the Apollo Lunar Surface Experiments network concluded in 1977. With a remarkable 20-fold increase in sensitivity near 1 Hz, 100 samples per second, and 24-bit analog-to-digital conversion, the VBBZ promise significantly improved data quality, while the CH7 instrument will provide data comparable to the Apollo short period seismometer but with better sampling and acquisition. Their strategic locations will also enable the exploration of previously uncharted lunar structures, including the south hemisphere highlands and the never seismically explored farside.PhD Research Objectives:1. Event Classification: The first objectives of the PhD will be to classify the observed events in the framework of the activities of the Lunar Quake Service, operated by IPGP and to therefore distinguish between Deep moonquakes, shallow moonquakes, impacts and thermal moonquakes For all events identified as Deep moonquakes, the next step will be to identify those associated to the near side sources, already detected by Apollo, and those potentially associated to new deep moonquakes sources located on the farside of the Moon. For the later, he will also develop technics for detecting them on the two available stations, VBBZ and LS. For all Deep moonquakes, the PhD will develop waveform matching algorithm, able not only to identify the DMQ sources from those already detected, but to generate progressively stacks of the DMQs seismograms, able to extend toward long period high SNRs and to characterize the seismic moment and the source cutoff of the events2. Seismic Noise Analysis: The second objective of the PhD will be to analyze the VBBZ seismic noise and to quantify the frequency-magnitude relations of the DMQs and to search for possible asperities in the DMQs fault planes, by comparing all detected events of a given source at high frequency and therefore identifying small differences in the waveforms associated to slight differences in the location of the rupture initiation. This will allow to better understand the long period seismic noise of the Moon and the existence of a possible DMQ hum, associated to small but repeating DMQs.3. Inversion Studies: The last objective of the PhD will be the inversion of all identified DMQs in terms of elastic and attenuation/diffusion structure. This will be made by inverting all travel times from the DMQs, either measured by FSS, LS or Apollo, as well as attenuation spectra and envelops of the stacked waveforms of DMQs. The inversion will be a joint structure-location inversion with Bayesian techniques and mineralogical models. A special focus will be made on the deeper interior of the lunar mantle, which might be the place for partial melting. In this inversion, geodetic data (moment of inertia, density) and tidal data from LLR will be also used and inverted. The inversion data set will also be completed by the travel times of the large impacts to be detected by FSS, when located by crater search and/or flash location.The PhD research will culminate in an interpretation of the inversion results, shedding light on lunar formation and evolution, and revealing lateral variations in the deep lunar mantle, including those related to the lunar dichotomy.The IPGP team plays a key role in both the FSS/VBBZ and the LS/ChangE’7 missions. The PhD director is the lead scientist for the VBBZ onboard FSS and serves as the chief scientist for the international LS team. This research will involve collaboration with FSS and ChangE’7 science teams and active participation in the Lunar Quake Service frontline team. IPGP is renowned as one of the world’s leading laboratories in planetary seismology, offering a unique and enriching environment for this research.For more Information about the topics and the co-financial partner (found by the lab !);contact Directeur de thèse –Then, prepare a resume, a recent transcript and a reference letter from your M2 supervisor/ engineering school director and you will be ready to apply online before March 14th, 2025 Midnight Paris time !

Expected salary

Location

Paris

Job date

Wed, 05 Feb 2025 06:22:23 GMT

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