Seismic detection of a 600-km solid inner core in Mars

Area of Science:

• Planetary Science
• Seismology
• Geophysics

Background:

• Rocky planet cores influence composition, thermal evolution, and magnetic history.
• Martian core is known to be at least partially liquid, but solid state is unconfirmed.

Purpose of the Study:

• To determine if Mars has a solid inner core using seismic data.
• To characterize the properties and implications of a Martian inner core.

Main Methods:

• Analysis of seismic data from the InSight mission.
• Identification of seismic phases (PKKP, PKiKP) indicative of an inner core.
• Inversion modeling to constrain inner core radius and properties.

Main Results:

• Demonstrated the presence of a solid inner core on Mars.
• Constrained the Martian inner core radius to 613 ± 67 km.
• Observed a ~30% compressional velocity jump at the inner core boundary.

Conclusions:

• Martian inner core likely contains segregated light elements from core crystallization.
• Provides a key data point for understanding Mars's thermal and chemical state.
• Informs models of Martian magnetic field evolution and planetary dynamo generation.