Overview

• Reanalysis of eight clear marsquakes shows high‑frequency seismic waves were delayed and scrambled by localized mantle heterogeneities up to about 4 kilometers across.
• The fragments are interpreted as relics of ancient giant impacts and magma‑ocean crystallization, forming a fractal pattern of a few large blocks surrounded by many smaller pieces.
• Findings draw on NASA’s InSight dataset of 1,319 recorded quakes, including two recent meteorite impacts that produced ~150‑meter‑wide craters and sent waves deep into the mantle.
• The persistence of these features indicates sluggish interior mixing on Mars without plate tectonics, unlike Earth where vigorous convection would erase such structures.
• The peer‑reviewed study underscores implications for stagnant‑lid worlds like Venus and Mercury and strengthens the case for deploying multi‑station seismic networks to map Mars’ interior more fully.