Past earthquake timing and magnitude along the Inglewood fault, Taranaki, New Zealand
Several active normal faults in the onshore and offshore regions of Taranaki are capable of generating large earthquakes and associated strong ground shaking. Historical earthquakes are concentrated offshore of Cape Egmont, and no significant earthquakes have been detected along the major onshore surface faults. The northeaststriking Inglewood fault is a major onshore, southward-dipping normal fault. It has a known length of c. 20 km and an average scarp height of c. 3 m on landforms less than about 15,000 yrs old. Three subsurface excavations at two sites along the Inglewood fault about 15 km from New Plymouth have revealed three surface fault displacements during the last c. 13,000 years. Earthquakes resulting in about 1.2 m of surface displacement occurred at c. 3,500 radiocarbon yrs BP; between 4,000 and 9,000 radiocarbon yrs BP; and between 10,000 and 13,000 radiocarbon yrs BP, judged by the amount of vertical offset of dated volcanic ash layers. Based on average single-event fault slip values of 1.2-3.0 m and a fault length of 20-30 km, the estimated earthquake magnitudes associated with these past movements range from Mw 6.7 to 7.2.
Alloway, B. V. 1989. The late Quaternary coverbed stratigraphy and tephrochronology of northeastern and central Taranaki. Unpublished Ph.D thesis, Dept. of Soil Science, Massey University, Palmerston North.
Alloway, B. V., Stewart, R. B., Neall, V. E., Vucetich, C. G. 1992. Climate of the last Glaciation in New Zealand, based on aerosolic quartz influx in an andesitic terrain. Quaternary Research 38: 170-179.
Bonilla, M. G., Mark, R. K., Lienkamper, J. J. 1984. Statistical relations among earthquake magnitude, surface rupture length, and surface fault displacement. Bulletin of the Seismological Society of America 74:2379-2411.
Eiby, G. A. 1968. An annotated list of New Zealand earthquakes, 1460-1965. New Zealand Journal of Geology and Geophysics 11:630-647. DOI: https://doi.org/10.1080/00288306.1968.10420275
Eiby, G. 1973. A descriptive catalogue of New Zealand earthquakes. Part 2 - Shocks felt from 1846 to 1854. New Zealand Journal of Geology and Geophysics 16:857-907. DOI: https://doi.org/10.1080/00288306.1973.10555229
Hanks, T. C., Kanamori, H. 1979. A moment magnitude scale. Journal of Geophysical Research 84: 2348-2350. DOI: https://doi.org/10.1029/JB084iB05p02348
Hull, A.G., Matsuda, T. 1981. Late Quaternary faulting near Inglewood, North Island, New Zealand (Abstract). Geological Society of New Zealand, Hamilton Conference, Programme and Abstracts: p. 52.
King, P. R., Thrasher, G. P . 1992. Post-Eocene development of the Taranaki Basin, New Zealand. American Association of Petroleum Geologists Memoir 53:93-118.
Latter, J. H. 1991. Seismicity and surveillance at New Zealand volcanoes. Programme and Abstracts Joint Annual Conference of Geological Society of New Zealand & New Zealand Soil Science Society. Geological Society of New Zealand miscellaneous publication 59A: p. 82.
Neall, V. E. 1972. Tephrochronology and tephrostratigraphy of western Taranaki (N108-109), New Zealand. New Zealand Journal of Geology and Geophysics 15:507-557. DOI: https://doi.org/10.1080/00288306.1972.10423983
Neall, V. E. 1979. Sheets P19, P20, and P21 New Plymouth, Egmont and Mnnnin. "Geological map of New Zealand 1:50,000" 1st Edition. DSIR, Wellington.
Nodder, S. D. 1993. Neotectonics of the offshore Cape Egmont fault zone, Taranakl Basin, New Zealand. New Zealand Journal of Geology and Geophysics 36: 167-184.
Robinson, R., Calhaem, I. M., Thomson, A. A. 1976. The Opunake, New Zealand, earthquake of 5 November 1974. New Zealand Journal of Geology and Geophysics 19:335-345. DOI: https://doi.org/10.1080/00288306.1976.10423563
Smith, W. D., Berryman, K. R. 1986. Earthquake hazard in New Zealand; inferences from seismology and geology. In: Reilly, W. I.; Harford, B. E. (eds). Recent Crustal Movements of the Pacific Region. Royal Society of New Zealand bulletin 24:223-243.
Copyright (c) 1994 A. G. Hull
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