 The region experienced a catastrophic earthquake and tsunami with an estimated magnitude of 9 in 1667, a magnitude 8.2 event in 1952, a 1968 quake measuring 8.3 , and one in 2008 measuring 7.1, all bearing the name "Tokachi-Oki", and a 1973 quake to the immediate north along the Kuril Trench plate boundary called the 1973 Nemuro-Oki earthquake.As of 3 October 2003, a total of 65 aftershocks were reported near the main shock epicenter.At least one major tremor occurred, measuring magnitude 7.0 on the Richter scale.