Figure3-4 Extension and compression in the Hokkaido region.

The directions of the two straight lines that cross each other in the figure are those of the maximum extension (or minimum compression; red) and the maximum compression (or minimum extension; blue), respectively. Also, the lengths of the straight lines are in proportion to the amount of the extension or compression.

[Compiled from data from "Active Faults in Japan, Revised Edition" and Geographical Survey Institute]

A: The past approximate 100 years.


Compression in eastern Hokkaido from the southeast to northwest has been pronounced due to the subducting Pacific Plate, while extension is evident on the Oshima Peninsula(Osima Hanto). The high value for the area near Yubari-si (Yubari City) is thought to be due to coal mining and other factors.

B: The past approximate 10 years.


Compression in eastern Hokkaido from southeast to northwest is apparent due to the subducting Pacific Plate.