1987 Edgecumbe earthquake

1987 Edgecumbe earthquake

Date	2 March 1987
Origin time	1:42 pm NZDT (UTC+13)
Magnitude	6.5 Mw
Depth	8 kilometres (5 mi)
Epicenter	37°53′S 176°50′E / 37.88°S 176.84°ECoordinates: 37°53′S 176°50′E / 37.88°S 176.84°E
Areas affected	New Zealand
Tsunami	None
Casualties	35 injured

Commemoration stone of the 1987 earthquake in Edgecumbe.

The 1987 Edgecumbe earthquake measured 6.5 on the moment magnitude scale and struck the Bay of Plenty region of New Zealand on 2 March. The shock was centred on the town of Edgecumbe and occurred just after 1:42 pm. at a shallow depth of approximately 8 km. It was one of the most damaging New Zealand's North Island has experienced in recent decades, with approximately 50% of the houses damaged. There was extensive damage to a local milk factory, with large storage tanks toppled. Kawerau was another nearby town that suffered damage and Whakatane was also badly shaken. An 80-tonne New Zealand Railways DC class locomotive was thrown onto its side.

There were no fatalities;^[1][2][3] one person died at the time as a result of a heart attack.^[4] A foreshock just minutes before had cut the power supply and many people had moved away from heavy machinery and out of their houses. The largest aftershock was measured at 5.2 and struck at 1.52 pm.

A crack 7 kilometres (4.3 mi) long opened in the Rangitaiki Plains near Edgecumbe. It is now known as the 'Edgecumbe Fault'. At one point, the land close to the fault dropped 2 metres (6.6 ft). Railway tracks were twisted and bent, and a diesel-electric locomotive toppled over.

The epicentre was approximately 2.24 kilometres (1.39 mi) south-south-east of the town of Matata, or 15 kilometres (9.3 mi) north-north-west of Edgecumbe.^[5] The intense ground shaking led to a large number of ground surface failures, including sand boils, ridge-top shatters and debris avalanches on steeper slopes.^[6]

See also

• List of New Zealand earthquakes

References

1. McSaveney, Eileen (1 December 2010). "Historic earthquakes - The 1987 Edgecumbe earthquake". Te Ara - the Encyclopedia of New Zealand. Archived from the original on 7 January 2011. Retrieved 13 February 2011.
2. "1987 Edgecumbe earthquake" (PDF). Rumblings Issue 19. Earthquake Commission. July 2009. Archived (PDF) from the original on 2 January 2011. Retrieved 13 February 2011.
3. "M 6.5, Edgecumbe, March 2, 1987". GeoNet. Retrieved 13 February 2011.
4. "Earthquake: Edgecumbe". Christchurch City Libraries. Retrieved 13 February 2011.
5. New Zealand Department of Scientific and Industrial Research Staff (1987). "The March 2, 1987, Earthquake Near Edgecumbe, North Island, New Zealand". Eos 68: 1162–1171.
6. Franks, C.A.M. (1988). "Engineering geological aspects of the Edgecumbe, New Zealand earthquake of 2 March 1987". Quarterly Journal of Engineering Geology 21 (4): 337–345. doi:10.1144/GSL.QJEG.1988.021.04.06.