From Iceland to Mars: Fault Scaling and Tectonic Insights from an Earth Analogue

Faults provide key evidence for a planet’s tectonic history, especially where direct geophysical data are scarce. Fault geometry analysis is essential for understanding tectonic deformation [1] and seismic potential [2]. Thorough fault geometry analysis constraints fault evolution mechanical response [3,4]. Marsquakes at Cerberus Fossae, Mars [5] which were detected by InSight mission’s seismometer renewed interest in Martian tectonics, and underscored the significance of extensional fault systems. Memnonia Fossae is a region hosting prominent extensional structures similar to Cerberus Fossae. Yet, these structures in Memnonia Fossae are much older than the ones in Cerberus Fossae, which provides a valuable opportunity to explore the long-term evolution of fault systems on Mars. However, due to the challenges in obtaining high-resolution topographic data [6], fault geometry studies on Mars are still limited. Therefore, to address this limitation, we use the Reykjanes Peninsula in Iceland as a terrestrial analogue, where active tectonic processes in basaltic terrains reflects those believed to occur on Mars. The objective of this study is to evaluate and compare the geometric properties and scaling relationships of normal faults in Memnonia Fossae region on Mars and Reykjanes Peninsula in Iceland, providing insights into fault growth mechanisms at a planetary scale.

Previously, we obtained a maximum displacement-to-length (D_max/L) ratio of 0.007 by analyzing fault scaling in Memnonia Fossae using remote sensing data from 100 faults. In this study, we focused on the Reykjanes Peninsula, and we collected structural measurements from 74 faults and fractures across 180 locations, recording parameters such as strike, dip, opening throw, shear, and extension vectors. Alongside field measurements, the Arctic DEM and drone imagery were employed also for less accessible faults.  The integration of field measurements, remote sensing, and drone imagery enabled a detailed characterization of fault geometry and displacement. The D_max/L ratio derived from Reykjanes peninsula was 0.006, closely corresponding to values derived for Memnonia Fossae and aligning with fault scaling observation in volcanic terrains on Earth. The observed similarities between faults in Reykjanes and Memnonia Fossae indicate that comparable fault growth processes may operate in both regions despite differences in age and origin. Reykjanes faults are part of an active plate-boundary rift zone on Earth, whereas Memnonia faults formed in the ancient crust of a single-plate planet. Comparing older and younger faults offer insights into the tectonic evolution of Mars and demonstrates the value of Earth-based multi-source datasets in planetary studies.

Figure 1: Dmax/L ratio comparisons of Memnonia Fossae, Reykjanes, and volcanic rocks on Earth [7].

 

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