If you track your sleep with the Jawbone Up and happen to live near the epicenter of Sunday's earthquake in Northern California, there's likely an anomaly in your sleep data.
Jawbone has released data culled from thousands of Up wearers in the San Francisco Bay Area who track their sleep with the wearable fitness-tracking bracelet. It shows a direct, if unsurprising, correlation between the percentage of Up wearers awoken when the quake struck at 3:20 a.m. PT and their proximity to the epicenter.
A blog post Monday on Jawbone's website notes that 93 percent of Up wearers in Napa, Sonoma, Vallejo, and Fairfield -- who were less than 15 miles from the epicenter -- woke up at the same time. Further from the most violent shaking, in San Francisco and Oakland, just over half of Up wearers woke up. By the time you get 75 to 100 miles from the epicenter, in places like Modesto or Santa Cruz, pretty much everyone managed to sleep through the quake.
The quake actually ruined the night's sleep for many people near the epicenter, too. Jawbone says that 45 percent of people within 15 miles of the quake's nexus stayed up the rest of the night. Some certainly had to spend that time cleaning up, and perhaps some were among the dozens injured in the quake.
Here's a look at a graph of Jawbone's data: