If you don't have one or are having trouble locating your bubble level, Android phones can actually use Google search to produce a simple bubble level to use.

Google is rolling out a global earthquake detection system using Android smartphone’s accelerometers. While seismometers would be preferred, this approach offers a more cost-effective way to identify ...

Google’s Android Earthquake Alerts system crowdsources data from smartphone accelerometers to detect seismic activity. The system has detected over 18,000 earthquakes and alerted millions across ...