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Effects of a major earthquake near Bougainville, 20 July 1975

Created 07/03/2026

Updated 07/03/2026

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On 20 July 1975 a major earthquake (MS7.9) shook the northern islands of the Solomon Islands chain. Damage amounting to at least $300,000 (Australian) occurred in the southern Bougainville/Shortland Islands region, where earthquake intensities were estimated to be MMVII-VIII. A tsunami with maximum amplitude of about two metres followed the earthquake and caused further damage. The earthquake caused landsliding, liquefaction, subsidence, slumping of roads and wharfs, and damage to villages, small government and mission buildings, and to the mining installations at Panguna. Aftershock epicentres were in a roughly elliptical area of 12 500 square kilometres off the southwestern coast of Bougainville. Focal depths were in the range 30-70 km. A fault-plane solution and the pattern of aftershocks indicate that the principal earthquake was associated with underthrusting of the Solomon Sea crust beneath Bougainville, in a northeasterly direction and with a dip of about 37°. The faulting associated with the 20 July 1975 earthquake appears to be the extension of faulting associated with a 1974 earthquake series. An aseismic zone, centred at 6°S, 154°E, exists immediately northwest of the 1975 earthquake fault zone, between zones where major earthquakes have occurred since 1970. It is considered to be a likely place for a major earthquake in future.

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Field Value
Title Effects of a major earthquake near Bougainville, 20 July 1975
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/en/dataset/a722e93b-5672-413a-bdd9-98ff42b735f2
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        146.0,
        -12.0
      ],
      [
        162.0,
        -12.0
      ],
      [
        162.0,
        -2.0
      ],
      [
        146.0,
        -2.0
      ],
      [
        146.0,
        -12.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Effects of a major earthquake near Bougainville, 20 July 1975". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/effects-of-a-major-earthquake-near-bougainville-20-july-19758