When a series of earthquakes hit Japan on Wednesday night, three days after the anniversary of the disastrous Tohoku quake and tsunami last year, many of the same cities and towns had to evacuate in what must have seemed like a nightmarish sequel. Fortunately, nobody was hurt and nothing was damaged this time around. The first quake hit off Japan's west coast, like last year's, but it was not nearly as strong, registering 6.8 on the richter scale compared with last year's 9.0. A second, registering 6.1, hit closer to Tokyo, followed by three aftershocks registering below 6.0, the United States Geological Survey reported.
While a tsunami warning was issued, no wave ever materialized. "A swelling of 20 centimeters (8 inches) was observed in the port of Hachinohe in Aomori, northern Japan, about one hour after the quake struck the region," the Associated Press reported. Still, people took no chances. "The town of Otsuchi in Iwate prefecture, where more than 800 died in last year's tsunami, issued an evacuation order to all households along the coast as a precaution, said prefectural disaster management official Shinichi Motoyama."
In case you've forgotten some of the geology lessons gleaned a year ago, each full point on the richter scale representa a ten-fold increase in amplitude (that' basically the distance the ground travels when it shakes) and "each whole number step in the magnitude scale corresponds to the release of about 31 times more energy than the amount associated with the preceding whole number value," according to the United States Geological Survey. That means that while Wednesday's quakes definitely made themselves felt, they were significantly weaker than last year's massive temblor.