Take another look at the pictures. Buildings miles inland were wiped out and even entire islands got submerged. How far away from the ocean do you propose people should live?
I remember when the Mississippi River reached an unusually severe flood stage... homes 11 miles from the river got flooded.
Every point on, above, and below the face of the earth has risks.
Looks to me like they were damaged by earthquake and tsunami. You can see the water went far inland by the discoloration it causes. In this pic, note the discolored river and debris jammed at the bridges; I think the tsunami reached somewhere further upstream.