In a lot of places a 7.5 magnitude quake would be considered more that a "jolt."
From Tokyo's Mainichi, April 20:
TOKYO (Kyodo) -- A powerful quake with a preliminary magnitude of 7.5 struck northeastern and northern Japan on Monday, with a tsunami warning issued, the country's weather agency said.
The 4:53 p.m. quake registered upper 5 on the Japanese seismic intensity scale of 7 and occurred at a depth of 10 kilometers, according to the Japan Meteorological Agency. The tremors were also felt in parts of Tokyo.
The agency issued tsunami warnings for the Pacific coasts of Hokkaido, Aomori and Iwate prefectures, forecasting tsunami waves of up to 3 meters.
An 80-centimeter tsunami was observed at Kuji port in Iwate Prefecture, the agency said....
....MORE
Here's the Japan Meteorological Agency tsunami warning page.
And the US Geological Survey (also on blogroll at right)
https://earthquake.usgs.gov/earthquakes/map/?extent=23.64239,-239.58984&extent=53.85115,-166.46484
It looks like there have already been a couple M5.0+ aftershocks.
