1970 New Guinea earthquake

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1970 New Guinea earthquake
Date October 31, 1970 (1970-10-31)
Magnitude 7.0 Mw
Depth 42km
Epicenter Lua error in package.lua at line 80: module 'strict' not found.
Areas affected Papua New Guinea
Tsunami yes
Casualties 5–15

The 1970 New Guinea earthquake struck the eponymous island and shocked the city of Madang on October 31. Causing between five and fifteen fatalities, it rocked the island and sent landslides cascading down steep hills into poorly reinforced wooden huts. The area that experienced the most powerful intensity extended 20 kilometers (12 mi) out from the epicenter. Underwater landslides triggered by the earthquake caused minor tsunami over about 100 km of coast and severed underwater cables in several places.[1]

Geography and geology

The earthquake took place near Madang, approximately 350 miles (563 km) northwest of Port Moresby. Generally, it was on the northeast coast.[2] The earthquake is thought to have been a result of strike-slip faulting in the area of complex structure along the boundary between the Pacific and Australian Plates.[3] Registering a Richter scale magnitude of 7.0, the earthquake took place at 7:53 am HST. Ray Sundean, the director of the Tsunami Warning Center in the area, cited the area as "one having frequent earthquaks [sic]."[2]

Damage and casualties

The earthquake resulted in five direct fatalities (up to fifteen)[4] and ten to twenty injuries.[4] Felt throughout the entire island of New Guinea, it caused extensive damage in the city of Madang, where it killed three people.[5] As a result of the earthquake, several homes buckled and cracks appeared in streets.[6] On the coast of the island, the earthquake cut off a cable connecting telephone units for Australia and Guam.[5] Initially officials were worried of a tsunami risk though the earthquake did not produce any.[2] This was due to a dramatic recession of water levels near the epicenter, followed by a rise that at one point measured Lua error in Module:Convert at line 272: attempt to index local 'cat' (a nil value)..[4] When a canoe was inverted by this change, three people were killed.[4]

Its maximum intensity of VIII (Severe) was restricted to a zone 20 kilometers (12 mi) from the epicenter (including the epicenter). Up to 70 kilometers (43 mi) away from the epicenter, damage measuring intensity VII (Very Strong) was recorded. Landslides caused most of the deaths (which the Catalog of Tsunamis in the Pacific, 1969–1982 lists as 15), which occurred in wooden huts damaged by the shock and crushed by rock.[4] The number of huts damaged totaled more than 800.[4] The city most damaged by the earthquake was Madang. Houses with poor earthquake engineering such as those with weakly reinforced frames performed poorly in the earthquake. 45 percent of the city's steel water tanks were beyond repair.[4]

References

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  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Soloviev, S.L., and Kim, K., p. 32.
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