On the Stability of Mantle-Sensitive P-Wave Interference During a Secondary Microseismic Event

• Published in: Geophysical Research Letters
• Main Authors: Tomasetto, L., Boué, P., Stehly, L., Ardhuin, Fabrice, Nataf, H.-c.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2024
• Subjects: ambient noise; body waves; secondary microseisms; seismic interferometry; Greenland
• Online Access: https://archimer.ifremer.fr/doc/00887/99903/110021.pdf; https://archimer.ifremer.fr/doc/00887/99903/110022.pdf; https://doi.org/10.1029/2023GL108018; https://archimer.ifremer.fr/doc/00887/99903/

Body wave extraction from oceanic secondary microseismic sources with seismic interferometry provides alternative information to better constrain the Earth's structure. However, sources' spatiotemporal variations raise concerns about travel time measurement robustness. Therefore, we study the cross-correlations’ stability during a single oceanic event. This study focuses on 3 days of data and three seismic arrays' combinations between 8 and 11 December 2014 during storm Alexandra, a “weather bomb” event in southern Greenland. We use the WAVEWATCH III hindcast to model P-wave noise sources and assess the impact of short-term source variations on cross-correlations. Model-based cross-correlations compared to data show coherent delays to reference 3D Earth models (∼0–3 s) confirming the robustness of the source model which could explain minor travel time variations (≤1 s). Key Points Teleseismic P-wave sources in the secondary microseismic band are inferred from a hindcast oceanographic model Seismic interferometry methods are applied to a “weather bomb” event between 8 and 11 December 2014 using an adaptive station pair selection Three-hour synthetic cross-correlation functions are compared to data to assess the impact of continuously varying sources on travel times Plain Language Summary Ocean wave interactions are a significant source of constant seismic wave emissions, known as ambient noise. Methods using correlations between seismic recordings recently highlighted surface waves and, more importantly, body waves to extract properties of the Earth's deep interior. These studies either use continuous recordings to infer medium properties, or focus on wave propagation from a specific storm. However, concerns about measurements can come from the broad oceanic source constantly changing in space and time. We model seismic recordings for 3 days during a powerful oceanic storm in southern Greenland, 8–11 December 2014, to assess the source variations' impact on body wave arrival times. We then compare it to data and ...