The newer smartphone can work as basic seismometers. Seismometer is a device used to determine changes in the ground surface vibration, which is usually associated with the earthquake.
If you have smartphone or computer tablet, uses Android or iPhone/iPad and you want to have an application to detect an earthquake, just install the application named Seismograph.
For tablet computer and Android smartphone :
• Open Play Store
• Search the App using keyword: Seismograph
• I choose Seismograph from Atrius, you can choose from others.
• Install the application
• After installed, run the application
• To check the function : try to move the smartphone, change the tilt, give a vibration, etc. you will see the change of graph.