May 2, 1930 Tsunami: Mid-Norway

Reference #12903:

The fjord is 25 to 30 km long and a maximum of 500 to 600 m deep. The slide occurred in the early morning at an exceptionally low tide.

From the observed changes in water depth it has been calculated that about 25 million m3 of soil had been moved by the three first-mentioned slides (Vogt, 1943).

A few minutes later a 600 to 700 m long slide at Orkanger, approximately 2 km away, destroyed some piers and harbour works.

Three kilometres from Storaunet the Ofstad-Sandlokken telephone cable crossed the fjord at a water depth of a maximum of 300 to 350 m. At 7:55 a.m. the cable was broken, indicating that the slide had propagated from Storaunet with a speed of about 25 km/hour.

Approximately 18 km further along the fjord, the Vorpenesset-Stadsbygden cable crossed at a water depth of 500 m. Failure of this cable at 9:40 a.m. corresponded to an average speed of propagation of 10 km/hour since the occurrence of the initial slide.

Reference #4139:

Large flood wave, Orkdalsfjorden

Reference #11164:

1930 May 02, Mid Norway 63.317 N 9.85 E, probable tsunami.

Reference #13255:

A similar underwater slide to that in 1888 in Trondheim occurred in 1930 in Orkdalsfjord. This slide set off several other smaller slides in which telephone cables were severed. Workmen at a newly placed fill embankment of about 1000 cu m at Orkanger first noticed a small wave on the water, after which the fill material started to slide. Shortly after a large flood wave came which caused considerable damage along the shore. It is estimated that this slide (or slides) comprised a total of 25 mill cu m of material. The flood wave was noticed more than 30 km from the slide area, and the underwater cables were broken after the wave had passed (Vogt 1943, p. 8). The cables must, therefore, in all probability have been broken by slide masses. The slide moved with a velocity of 7 m per second up to the first cable break, and a velocity of about 3 m per second between the cable breaks. The flood wave must, therefore, have had a greater velocity of displacement than that (cp. G. Holmsen 1934, p. 6-7).