The NASA Pi Day Challenge Slideshow | NASA/JPL Edu

The NASA Pi Day Challenge Slideshow | NASA/JPL Edu

Quake Quandary

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During a seismic event on Mars, or a “marsquake,” a type of seismic wave called surface waves travel outward from the epicenter, across the planet in all directions. Scientists expect these surface waves to arrive at NASA’s InSight lander, designed to study the quakes, at three different times: R1, when the first wave arrives, having traveled the shortest distance from the epicenter to the lander; R2, when the second wave arrives, having traveled the other way around Mars; and R3, when the first wave again impacts the lander, having traveled all the way around Mars. Let’s imagine InSight records marsquake waves at the following Earth times:

R₁ = 08:38:09.4 UTC

R₂ = 10:04:48.2 UTC

R₃ = 10:25:43.0 UTC

*Note times are in UTC, which is written in hh:mm:ss format.

Use the formulas below to determine the velocity (U) in rad/s of the surface wave, the distance in radians on the sphere from InSight to the epicenter (Δ), and the time the marsquake occurred (t₀).

Learn more about the InSight Mars lander