September 8, 1880 Earthquake: Gisborne, New Zealand

Reference #5324:

1880, September 8, 21:30 local time.

According to the Poverty Bay Herald (9 September 1880), "precisely at 10 pm last night [Sept 8], there was a very perceptible, albeit, gentle shock of earthquake experienced [probably at Gisborne, Poverty Bay], the direction of the undulation being from East to West. There were this morning a considerable number of fish, all dead, cast up on the banks of the rivers and bays."

Despite the paucity of information, this event is almost certainly a tsunami, as the deposition of fish is a key indicator of tsunami. Further, the description of a mild earthquake, not widely felt, followed by a tsunami is very similar to that for the "tsunami" earthquakes on 25 March 1947 (q.v.). The 1947 March 25 (UT) MW7.0-7.1 MS7.2 ML5.9 earthquake (q.v.), centred about 60-70 km offshore was felt with an intensity of MM4 in Gisborne and was the maximum elsewhere along the coast, while the tsunami had maximum water level close to the shore at Gisborne port of about 1.5-1.8 m, consisted of several large waves and a number of smaller waves over several hours, the first of which arrived about 30-40 minutes after the earthquake. The 1880 tsunami would have similarly occurred close to the time of high tide (as calculated by NIWA Tide Forecaster).

Hence, the epicentre and magnitude of the March 1947 earthquake are tentatively adopted.