Historical Seismograms - Evidence from the AD 2000 Izu Islands ...

Seismograms Before 1963 in the South- West Pacific 459At various times Imamura, Jaggar, and other low magnification instrumentswere in use at Bunnythorpe (BUN, 1932); East Cape (ECZ, 1934-37); Greymouth(1932-42); Monowai (MNW, 1935); Napier (NPR, 1953-55); Stratford (STZ, 1934-39); Takaka (TAK, 1931-51).In the period 1930-50 several privately constructed stations operated. No continuousfiles of records from these stations are known to have survived, but theWellington archive contains a few seismograms of large events.3. SamoaThe University of Gzttingen established the Samoan Observatory at Apia (API)at the end of last century. A Wiechert horizontal instrument began recording in1902, and a vertical was added in 1914. Seismograms covering the period from 1902December to 1913 April are in Giittingen, in the care of the Institut fur Geophysikof the University (P.O. Box 876, Gottingen 3400). No analyses are known to havebeen made or published. A list of 93 shocks recorded between 1913 and 1920 waspublished by Angenheister (1922). The records for this period have not yet beenlocated, but are most probably in the Wellington archive, where all later recordsare filed. New Zealand assumed responsibility for the station in 1920. A Wood-Anderson instrument was installed in 1948, and a second component added in 1957,when the station at Afiamalu (AFI) was established on a better site farther inland,and the Wiechert instruments dismantled. Afiamalu was provided with a shortandlong-period vertical and a long-period horizontal Benioff seismometer. In 1962Afiamalu became a World-Wide Standard Seismograph Station.4. French Territories in the Pacific4.1. The ORSTOM NetworkEarthquake recording in the bench territories of the Pacific and in the Condominiumof the New Hebrides (now Vanuatu) during the period of this report wasthe responsibility of the Office de la Recherche Scientifique et Technique Outremer(ORSTOM), and the seismograms are stored at the regional headquarters inNoumka. They axe reported to be in excellent condition. All stations have Coulomb-Grenet instruments. A single vertical component began recording at a site nearNoumka in 1954, and in 1957 horizontal components were added and the installationmoved to a new site. A second three-component station was established atPort Vila (PVC) in the New Hebrides in the same year, and a vertical componentat Koumac (KOU), New Caledonia, in 1959. The stations at Luganville (LUG) inthe New Hebrides and Ouanaham (OUA) in the Loyalty Islands were establishedonly at the very end of 1963. Each has a short-period vertical instrument, andLuganville has a long-period instrument as well.4.2. Tahiti (TAH)In 1957 Dr. Claude Blot installed two Labrouste horizontal pendulums at a site onthe isthmus of Taravao, as part of the International Geophysical Year programme.The station was destroyed by hurricane] but some records are believed to be heldat the Institut de Physique du Globe in Strasbourg.