Beneath the cerulean waters of Monterey Bay, just a few miles southeast of Santa Cruz, California, a never-before-seen cluster of faults has been found lurking on the ocean floor.

These newly spotted wrinkles in Earth’s crust, described in a paper published today in Science, are still largely a mystery. We can’t say much about their size, shape, or how active they are. Still, the findings show that even in one of the most seismically studied corners of the planet, fault maps of the ocean floor contain gaping holes. That’s a big problem, because if we don’t know where seafloor faults are, coastal communities are going to be in the dark about any earthquake or tsunami threats they might present.

The new