Last night, when I rested at ease in my living room, my cellular phone suddenly set up a shout: “Earthquake!, Earthquake!”. I picked it up, and shakiness began when I only read the first few letters of “Earthquake Early Warning Strong shaking is expected soon. Stay calm and seek shelter nearby.(Japan Meteorological Agency)”. This service is called “Area Mail Disaster Information Service” provided by docomo.
At my region, the shakiness was not so strong, it was just sindo 3. Sindo(震度) is a Japan Meteorological Agency Seismic Intensity Scale, see here about details. Japan has the nationwide Seismic Intensity observation system. So we can know about Seismic Intensity of each region immediately. If some areas exist nearby the epicenter and give no Seismic Intensity reports, we expect the areas have very terrible damages because we can understand the system itself is broken.
The main quake magnitude is only 6.4 last night. This is very lower than 2011 Tōhoku earthquake's, it was 9.0. But some areas had sindo 7. Why? Because a magnitude tells us an earthquake energy only. What shaking the earthquake gives to each region is a complete different story. It depends on depth, distance, and so on.
Anyway, we had no damage in my town, but Kumamoto prefecture a lot of people had serious damages by the earthquake. I’ll make some donation for earthquake relief though I don’t go there as a volunteer.