September 8, 2002 Tsunami: Bismarck Sea, Papua New Guinea

Reference #2661:

A moderate tsunami followed about 15 minutes after the earthquake. Run up heights on open coast were generally less than 1 m, but reached 1.5 m at Kauk and an estimated

3-4 m in west-facing bays on the islands, and on the mainland coast immediately east of Boiken.

The higher run-up in the west-facing bays was a funneling effect. In both Victoria Bay and Mushu Bay, the larger of the west-facing bays on Mushu Island, observers saw the water circulate counter clockwise around the perimeter of the bay, and reach maximum height in the eastern extremity of each bay. Logs were washed ashore amongst the houses at Buruwan on Victoria Bay and 50 m of land was inundated. Logs, coral and a moored dinghy were washed ashore in Mushu Bay. The reason for the higher run-up east of Boiken is less clear, but perhaps was due to the funneling of the tsunami between the coast and the islands. Tsunami effects were observed as far east as Murik Lakes; where water washed through the villages at ankle depth. The villages are on a low sand bar. In the west, a repeated rising and falling of the water level in the Aitape River of the order of 1 m above normal water level was observed at 6.45 to 7 am. In Wewak too, there was a fluctuation of the sea level at 6:45-7 am, the water draining out into the bay then returning passively to flood across the road, before subsiding to normal level. The drop in sea level was estimated to be 2 m, and the rise above normal sea level, 1.5-2 m. The fluctuations at 6:45 am appear to have been a second and discrete tsunami event.

Reference #11914:

It is notable that the amplitude and effects of the tsunami were greatest in the Boiken - Muschu Is. - Kairiru Is. area, about 70-80 km from the epicenter of the main earthquake and about 20-30km from the location of the CMT. In the area of maximum damage from earthquake shaking, between Boiken and the mouth of Hawain River, the tsunami was reported to have had turbulent, violent flow. At Victoria Bay at the eastern end of Kairiru Island, the tsunami was observed to approach from the southwest and swirled along the cost with an anti-clockwise motion depositing large logs and other debris. At these locations and on both northern and southern coasts of Muschu Island houses were swept away by the tsunami. These observations indicate that source of the tsunami was in this same general area, ie., the Boiken - Muschu Is. - Kairiru Is. area.

2002, September 8, 18:44:25.53 UTC. 3.260 South, 142.940 East, depth 13.0 km, 7.6 Mw HRV. (reference #9910)

2002, September 08, 18:44:25.38 UTC. 3.353 South, 143.014 East, depth 13 km, 7.59 Mw.

(reference #10476)