Earthquakes

In addition to wind, snow, and rain, we may have an earthquake during the trip. We had a large one last night at 1:45. The first tremors woke me up and then about five minutes later there was an even larger quake.

A few months ago, NHK, the national broadcasting system, started a system that gives you a few seconds (up to 15) of warning before the tremors arrive. It also tells how strong it will be. This at least gives you a chance to get under a table or something if it is going to be large.

The Japanese system for rating earthquakes is much more useful than the scientific system used in the US. Although the papers and TV give the Richter scaler reading, they primarily report using the Japanese system of 1 to 8. I do not have the actually explanation here but the following is my understanding of it:
1 - you can feel it if the conditions are right, sitting down in a multistory building, for example
2 - you can feel it, unless you are moving
3 - generally everyone feels it
4 - a few books or loose bricks may fall and it feels strong
5 - some damage to buildings, includes the first use of + and - to give a more graded evaluation
6 - extensive damage and some buildings collapse, uses + and -
7 - severe damage to buildings, roads, etc, also uses + and -
These numbers represent the human experience on the surface. The Richter scale indicates the intensity at the origin and may have little relevance to what happens on the surface, depending on the depth of the origin.

This is a bit like the Celsius and Fahrenheit temperature scales. The Celsius (Richter) scale is more convenient for science, but the Fahrenheit (Japanese) scale is better for relating the phenomenon to daily experience.