When I visited California for a couple of weeks, I stayed with my friend Caroline in her 5th floor apartment. While staying there, I had a feeling like something is shaking late at night. This was a very unpleasant feeling and I thought I was getting crazy. That’s when my friend told me about frequent but mild quakes in California. Since these small quakes are not even reported in the media, I set out to test this theory with the help of an app for Android called Vibrometer. And sure enough this app saved my sanity, when it measured some vibrations and gave a rough estimate of their magnitudes.
The Vibrometer app can be said to be a very cheap seismograph that uses the accelerometer sensor of your Android smart phone to measure the vibrations of the surface on which you have placed the phone. Even though this does not give very accurate results like the commercial seismographs used by the United States Geological Survey (USGS), but for home use this is not bad.
After installing the app, launch Vibrometer and then you have to place the phone on a smooth horizontal surface. The surface need not be horizontal, but it gives better results in my Samsung Galaxy phone for some reason. You would see some small vibrations even when surface is not visibly shaking, but that is normal. As you can guess, when the surface is shaken by an earthquake or by yourself, then these are displayed on your phone’s screen in form of a graph along with the maximum magnitude reached.
In the settings, you can set the alarm for a particular level of quakes. This way the app keeps running in the background and sounds an alarm the moment it detects the quakes of a certain level. You can also choose the type of beep sounds you want to use as the alarm. In addition to the Vibrometer app, you may also want to use the LastQuake app that receives data online from European Mediterranean Seismology Center (EMSC).
You can get the Vibrometer app for Android from https://play.google.com/store/apps/details?id=kr.sira.vibration.