An earthquake with a preliminary Richter magnitude of 5.5 struck north Japan on Friday, but has not yet resulted in a tsunami warning.

The quake shook Fukushima-ken Oki, in the north of Japan’s Honshu Island, and was followed within an hour by three strong aftershocks.

Although the earthquake immediately stoked fears for a nation still recovering from the aftermath of last year’s deadly earthquake, there have not yet been any immediate reports of danger, injuries, or deaths according to Reuters.

Friday’s quake, initially valued at a magnitude of 5.5 was later downgraded to a 5.2 magnitude, according to reports by the Japan Meteorological Agency. The agency said that the quake had struck parts of Ibaraki Prefecture, Fukushima, Saitama and Tochigi, with magnitudes ranging from 3 to 4. In Tokyo, 118 miles southeast of the quake’s epicenter, it was measured at a 2 magnitude.

In March of 2011, Japan was struck by an 8.9 magnitude earthquake that triggered a tsunami of devastating proportion, and was followed by a series of aftershocks. More than a year and a half later the country continues to carry on with large-scale clean up efforts, that could cost the nation as much as 10 trillion yen (or $125 billion), according to the most recent report from Tokyo Electric Power Co.

The effort to clear the more than 13 million tons of debris left over from the disaster has been described as the single biggest clean up Japan has had to orchestrate since repairing the damage of World War II. Officials have been working steadily to burn the debris, grind it into mulch, and clear it away. But the laborious clean up has not gone without protest from citizens: many residents of towns where debris is being relocated have voiced concern about the danger of taking on hazardous waste.

Government officials have maintained their position that the waste does not pose a threat and has not led to any elevation in radioactivity, but residents remain wary.