14:15 〜 14:30
[MIS18-03] Volcanism and Tectonism at Elysium Planitia on Mars Inferred From the InSight Seismic Observation
キーワード：火星、惑星地震学、インサイト
NASA’s InSight (2018–2022) performed seismic observation on Mars, improving our understanding of the Martian seismicity and internal structure significantly (e.g., Lognonné et al., 2023; Samuel et al., 2023; Khan et al., 2023). One of the interesting outcomes was that Cerberus Fossae, located in the Elysium Planitia and 1200 - 2300 km apart from the InSight landing site in the east, hosted some marsquakes.
The inverted focal mechanisms suggested fault slips to be seismic sources, implying that the red planet is still geologically and geodynamically active even though not as much as our planet (e.g., Brinkman et al., 2021; Perrin et al., 2022; Jacob et al., 2022). Furthermore, Stähler et al. (2022) investigated each marsquake family (e.g., low-frequency, high-frequency events) more systematically, paying attention to corner frequency and seismic moment. Through comparisons with slow and fast earthquakes, they proposed that the low-frequency marsquakes from Cerberus Fossae might be related to the crustal weakening due to partial melt beneath that region. More recently, Broquet & Andrews-Hanna (2023) performed stress field reconstruction at Cerberus Fossae, focusing on gravity anomaly distribution and surface fissure characteristics, and proposed an active mantle plume head beneath the lithosphere. These findings would allow us to better illustrate the past volcanism at Elysium Planitia, where one of the youngest lava flows has been proposed (e.g., Horvath et al., 2021).
In the presentation, following a review of InSight seismic observation and recent stress field inversion results, we discuss future seismic exploration strategies on Mars.
References:
• Brinkman et al. (2021), First focal mechanism of marsquakes, JGR: Planets, 126, 4, e2020JE006546.
• Broquet and Andrews-Hanna (2023), Geophysical evidence for an active mantle plume underneath Elysium Planitia on Mars. Nat Astron 7, 160–169.
• Horvath et al. (2021), Evidence for geologically recent explosive volcanism in Elysium Planitia, Mars, Icarus, 365, 114499.
• Khan et al. (2023), Evidence for a liquid silicate layer atop the Martian core, Nature, 622, 718–723.
• Jacob et al. (2022), Seismic sources of InSight marsquakes and seismotectonic context of Elysium Planetia, Mars, Tectonophysics, 837, 229434.
• Lognonné et al. (2023), Mars seismology, Annual Rev. Earth Planet. Sci., 51, 643-670.
• Perrin et al. (2022), Geometry and segmentation of Cerberus Fossae, Mars: Implications for marsquake properties, JGR: Planets, 127, 1, e2021JE007118.
• Samuel et al. (2023), Geophysical evidence for an enriched molten silicate layer above Mars’s core, Nature, 622, 712–717.
• Stähler et al. (2022), Tectonics of Cerberus Fossae unveiled by marsquakes, Nat Astron, 6, 1376–1386.
The inverted focal mechanisms suggested fault slips to be seismic sources, implying that the red planet is still geologically and geodynamically active even though not as much as our planet (e.g., Brinkman et al., 2021; Perrin et al., 2022; Jacob et al., 2022). Furthermore, Stähler et al. (2022) investigated each marsquake family (e.g., low-frequency, high-frequency events) more systematically, paying attention to corner frequency and seismic moment. Through comparisons with slow and fast earthquakes, they proposed that the low-frequency marsquakes from Cerberus Fossae might be related to the crustal weakening due to partial melt beneath that region. More recently, Broquet & Andrews-Hanna (2023) performed stress field reconstruction at Cerberus Fossae, focusing on gravity anomaly distribution and surface fissure characteristics, and proposed an active mantle plume head beneath the lithosphere. These findings would allow us to better illustrate the past volcanism at Elysium Planitia, where one of the youngest lava flows has been proposed (e.g., Horvath et al., 2021).
In the presentation, following a review of InSight seismic observation and recent stress field inversion results, we discuss future seismic exploration strategies on Mars.
References:
• Brinkman et al. (2021), First focal mechanism of marsquakes, JGR: Planets, 126, 4, e2020JE006546.
• Broquet and Andrews-Hanna (2023), Geophysical evidence for an active mantle plume underneath Elysium Planitia on Mars. Nat Astron 7, 160–169.
• Horvath et al. (2021), Evidence for geologically recent explosive volcanism in Elysium Planitia, Mars, Icarus, 365, 114499.
• Khan et al. (2023), Evidence for a liquid silicate layer atop the Martian core, Nature, 622, 718–723.
• Jacob et al. (2022), Seismic sources of InSight marsquakes and seismotectonic context of Elysium Planetia, Mars, Tectonophysics, 837, 229434.
• Lognonné et al. (2023), Mars seismology, Annual Rev. Earth Planet. Sci., 51, 643-670.
• Perrin et al. (2022), Geometry and segmentation of Cerberus Fossae, Mars: Implications for marsquake properties, JGR: Planets, 127, 1, e2021JE007118.
• Samuel et al. (2023), Geophysical evidence for an enriched molten silicate layer above Mars’s core, Nature, 622, 712–717.
• Stähler et al. (2022), Tectonics of Cerberus Fossae unveiled by marsquakes, Nat Astron, 6, 1376–1386.