Mars today is a planet that appears to be mostly shaped by wind, but that wasn’t always the case. A new map adds information to the hypothesis that “marsquakes” affected at least a part of the planet’s vast canyon, Valles Marineris, while the area contained spring-filled lakes.

When the damp sand got shaken up, it deposited itself in hills. NASA says the new map, based on observations from the Mars Reconnaissance Orbiter (which you can see below), adds credence to the theory that it was water that made these deposits.

“The conditions under which sedimentary deposits in it formed have been an open issue for decades,” NASA wrote in a press release. “Possibilities proposed have included accumulation in lakebeds, volcanic eruptions under glaciers within the canyons, and accumulation of wind-blown sand and dust.”

The map you see below was created by the U.S. Geological Survey, which has more extensive information on the findings at this website. The observations also produced a suite of research in recent years, such as this 2009 paper led by Scott Murchie at the Johns Hopkins University Applied Research Laboratory.