This sound is terrifying even a year later. It's the voice of Japan's 9.0 temblor and its aftershocks. Zhigang Peng at Georgia Tech’s School of Earth and Atmospheric Sciences converted the quake's seismic waves into sped-up audio files that we can hear.
The clip above was taken near the coastline of Japan between the nuclear reactor at Fukushima Daiichi and Tokyo. The initial blast is the 9.0 mainshock. Following that you can hear aftershocks, popping sounds, as the earth's plates slip into new positions.
Here's Peng's recording of the 2011 Japanese earthquake taken from seismic measurements thousands of miles away in California. The quake created subtle movements deep in the San Andreas Fault known as distant triggering.
You can hear the initial noise, which sounds like thunder and corresponds with the Japanese mainshock. Afterwards a continuous high-pitch sound, like rain turning on and off, reflects continuing tremor activity at the fault, as heard from afar in California.