Detection of seismic events on Mars: a lunar perspective

Abstract

The interior structures of planets are attracting more and more detailed attention; these studies could be of great value in improving our understanding of the early evolution of Earth. Seismological investigations of planet interiors rely primarily on seismic waves excited by seismic events. Since tectonic activities are much weaker on other planets, e.g. Mars, the magnitudes of their seismic events are much smaller than those on Earth. It is therefore a challenge to detect seismic events on planets using such conventional techniques as short‐time average/long‐time average (STA/LTA) triggers. In pursuit of an effective and robust scheme to detect small‐magnitude events on Mars in the near future, we have taken Apollo lunar seismic observations as an example of weak‐activity data and developed an event‐detection scheme. The scheme reported here is actually a two‐step processing approach: the first step involves a despike filter to remove large‐amplitude impulses arising from large temperature variations; the second step employs a matched filter to unmask the seismic signals from a weak event hidden in the ambient and scattering noise. The proposed scheme has been used successfully to detect a moonquake that was not in the known moonquake catalogue, demonstrating that the two‐step strategy is a feasible method for detecting seismic events on planets. Our scheme will provide a powerful tool for seismic data analysis of the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission, and China’s future lunar missions.

Repetitive marsquakes in Martian upper mantle

“…We here start by assuming that the currently used approaches could miss small-magnitude events buried in ambient noise. We subsequently employ the MF 29 – 31 and BL 32 – 34 identification methods to detect small-magnitude events (Supplementary Note 1 ; Supplementary Figs. 3 – 50 ) buried in noise.…”

“…In this work, we deploy two relatively unconventional search methods, recently introduced to the geophysics community: the matched filter (MF) 29 – 31 and the law of first digits, a.k.a. Benford’s Law (BL) 32 – 34 .…”

Distributed Blind Deconvolution of Seismic Signals Under Sparsity Constraints in Sensor Networks

“…, H T J ] T which allows to reformulate model (2) as 1) . We assume white Gaussian noise with covariance matrix Σ = blkdiag(σ 2…”

“…To this end, each geophone is additionally equipped with algorithmic and communication capabilities that allow a data processing and exchange with other geophones in the network. Such an architecture is particularly relevant for the exploration of a planet's subsurface such as on Mars or Moon [2] where an autonomous operation is required and a central processing entity might not be available. In this paper, we aim at taking a first step into a distributed seismic exploration method by focusing on the development of a distributed deconvolution method for seismic signals.…”

Variational Bayesian Learning for Decentralized Blind Deconvolution of Seismic Signals Over Sensor Networks

“…The latter allows for a cooperative processing of measured data. Such an architecture is particularly relevant for autonomous exploration of a planet's subsurface such as that on Mars or Moon [2], where an autonomous operation is required and a central processing entity might not be available.…”