← Back to Sessions

Super High Frequency Events: A New Class of Events Recorded by the Insight Seismometers on Mars

Session: Insight Seismology on Mars: Results From the First Martian Year of Data and Prospects for the Future [Poster]

Type: Poster

Date: 4/23/2021

Presentation Time: 11:30 AM Pacific

Description: 

We present a new class of seismic signals recorded by InSight’s seismometers on the surface of Mars, which we call super high frequency (SF) events [1]. The signals are of short duration (∼20 s), are often similar in amplitude, and feature high-frequency energy between ∼5 and 30 Hz that is dominant on the horizontal components. With this, the SF events share several key characteristics with the much longer lasting very high frequency marsquakes [2].

We use the continuous 20 samples per second (sps) data from the Very Broadband instrument to detect and characterize SF events. 100 sps data from the Short Period sensor are only partially obtainable due to bandwidth limitations, but they aid in analyzing the high frequency content of selected events and in distinguishing them from high-frequency noise. From June 2019 to May 2020, 780 SF events were detected. The events observed occur in repeatable patterns that last for weeks. Initially, the SF events were clustered in the hours before sunset, but later, they have been distributed across the evening period. From June 2020 to the end of the year, the seasonal changes at InSight’s location have led to persistently high levels of atmospherically-induced noise, and consequently, have greatly restricted the observation of SF events (In total 792 events until end of 2020).

Based on template matching techniques, we have identified 16 distinct event families that generally correspond to the temporal clusters. We infer these signals originate from close to the lander but not the lander itself. The majority of the events occur within 2 hours before or after sunset, a period with extreme temperature changes, which suggests that the origin of these events is thermal. The SF events resemble thermal events that have been observed on the Moon during the Apollo missions.

[1] Dahmen et al. (2020). Super high frequency events: a new class of events recorded by the InSight seismometers on Mars. JGR:Planets.

[2] Clinton et al. (2020). The Marsquake catalogue from InSight, sols 0–478. PEPI.

Presenting Author: Nikolaj Dahmen

Student Presenter: Yes

Authors