A major earthquake struck the west coast of Chile early this morning New Zealand time. The deep quake was located near the border with Bolivia and Argentina, and appears to have caused some injuries and damage, but no deaths have been reported.
The magnitude 7.7 earthquake struck at 4:41 a.m. New Zealand Daylight Time on Thursday November 15th 2007. It was located 40 km east-south-east of Tocopilla Chile (170 km north-north-east of Antofagasta, Chile; 1245 km north of Santiago, Chile) at a depth of 60 km.
The on-shore quake was probably due to movement between the Nazca and South American tectonic plates in the area where the Nazca Plate is sliding under South America. This morning’s earthquake occurred at the southern end of the rupture zone involved in the great quake (estimated at magnitude 8.8) of 1877. This 9th of May 1877 event destroyed the city of Iqueque and caused a destructive tsunami which reached New Zealand shores.
On the 11th of May 1877 an extraordinary swelling of the sea in Poverty Bay was observed at 4 a.m. Three hours later, a large wave rushed up the Turanganui River which rose 7 or 8 feet (more than 2 metres) in as many minutes but then quickly subsided. The crew of the s.s. Go Ahead, which was aground at the entrance to the river, had to scramble up the rigging as the wave came ashore. Further up the East Coast, cargo which had been unloaded at Port Awanui was swept away. [Mackay]
Writing in “Awesome Forces,” Willem de Lange reports that the 1877 event caused a maximum wave height of 3.7 metres in New Zealand. Another Chilean quake in 1960 caused a 3.5 metre wave, the largest of the 20th century.
Following this morning’s event, the Pacific Tsunami Warning Centre issued a tsunami warning for Chile and Peru. However, at 5:56 a.m. the warning was withdrawn, following a wave of only 7 cm being recorded at Antofagasta.
Five aftershocks of the magnitude 7.7 quake, with magnitudes between 4.6 and 5.7 have been recorded.
[Compiled from data supplied by the US Geological Survey and its contributing agencies, and the U.S. National Oceanic & Atmospheric Administration’s Pacific Tsunami Warning Centre. New Zealand historical information from: “Awesome Forces” Te Papa Press, Wellington, 1999; and Mackay, J.A., “Historic Poverty Bay and the East Coast, N.I., N.Z.” 2nd edition, 1966.]