The Long‐Lived and Recent Seismicity at the Lunar Orientale Basin: Evidence From Morphology and Formation Ages of Boulder Avalanches, Tectonics, and Seismic Ground Motion

Seismic hazard assessment of the Moon provides essential information for developing seismic‐resilient lunar bases where long‐term scientific exploration can be carried out. The 930‐km‐diameter Orientale basin has been proposed to be the landing site for the future human and robotic missions. Hence, we assessed whether the basin is seismically active and hazardous to the landed missions. For this, we relied on the local geology, mapped the boulder fall occurrences throughout the basin interior, characterized their morphology and formation ages, estimated the relative abundances of the shallow moonquakes and impact events, and modeled the seismic ground motion scenarios. Our study confirms that the Orientale basin is seismically active. The formation ages of boulder falls point to episodically occurring shallow moonquakes in the last eight million years. Our seismic ground motion simulations indicate that the shallow moonquakes are the major triggering sources for the origins of boulder falls in the basin. Although the Orientale basin may be locally hazardous to the future landed missions, seismically safe regions are also present in the basin. It is also a great place for the observation of local to globally occurring shallow moonquakes and we recommend a seismic observation network for this basin.

Figure: Wrinkle ridges and grabens are potential locales of shallow moonquakes within the Orientale basin.

 

Citation: Mohanty, R., Kumar, P. S., Raghukanth, S. T. G., & Lakshmi, K. J. P. (2020).

Journal of Geophysical Research: Planets, 125, e2020JE006553. https://doi.org/10.1029/2020JE006553 external link