OLR (1981) 28 (12) D. Submarine Geology and Geophysics 875

collision of lithospheric plates beneath the Fiji Plateau; present-day Tonga subduction appears the primary cause. The remnants of two paleosubduc- tion zones (Pacific-Phoenix and Tasman Sea) have been activated. Inst. of Geology and Geotechnics, Czech. Acad. of Sci., Prague, Czechoslovakia. (bas)

81:6594 Hong, Tai-Lin and Kazuya Fujita, 1981. Modelling

of depth phases and source processes of some central Aleutian earthquakes. Earth planet. Sci. Letts, 53(3):333-342.

Arrival times and relative amplitudes of P, pP, pwP, and sP phases are calculated using synthetic seismo- grams of short-period vertical records. Simple fracture events are used to model the forearc sub-surface structure; complex fracture events are recognized as well. The method may be used on events up to magnitude 5.7 and may involve propagating fractures and multiple events. Exxon Production Res. Co., P.O. Box 2189, Houston, Tex. 77001, USA. (bas)

81:6595 Hyndman, R.D. and R.M. Ellis, 1981. Queen

Charlotte [western Canada] fault zone: micro- earthquakes from a temporary array of land stations and ocean bottom seismographs. Can. J. Earth Sci., 18(4):776-788.

Eleven microearthquakes of depths between 9 and 25 km were located using 3 0 B S ' s deployed both east and west of the main fault zone. Predominantly strike-slip motion, with some underthrusting, on a near-vertical fault zone is suggested. Seismicity rates were close to predicted values. Dept. of Energy, Mines and Resources, P.O. Box 6000, Sidney, B.C., Canada VSL 4B2. (has)

81: 6596 Kimura, Gaku, 1981. Ahashiri Tectonic Line. Special

reference to the tectonic significance of the southwestern margin of the Kurile Arc. J. Fac. Sci. Hokkaido Univ., (Ser. 4, Geol. Miner- al.)20(1):95-111. Dept. of Geol. and Mineral., Hokkaido Univ., Japan.

81:6597 Li, Desheng, 1980. Tectonic frameworks of Bohai

Gulf and coastal basins, China..4eta oceanol, sin., 2(4):93-101. (In Chinese, English summary.) Scientific Res. Inst. of Petroleum Exploration and Development, Ministry of Petroleum, Peo- ple's Republic of China.

81:6598 Mair, J.A. and J.A. Lyons, 1981. Crustal structure

and velocity anisotropy beneath the Beaufort Sea. Can. J. Earth Sci., 18(4):724-741.

Crustal-scale seismic refraction data reveal a 4-5 km thick sedimentary layer overlying oceanic crust. The sedimentary layer has a compressional velocity of 1.8 km/s and a shear velocity of ~0.2 km/s; an oceanic layer 2A of 4.3 km/s, a layer 3A of 6.6 km/s, and a layer 3B of 7.6 km/s overlying an anisotropic (3%) upper mantle with a median velocity of 8.3 km/s are interpreted. The direction of maximum upper- mantle velocity suggests that a rotation of the Northwind Ridge-Chukchi Plateau away from the Barrow-Martin Point sector of Alaska may have occurred. Dept. of Energy, Mines and Resources, Ottawa, Ont., Canada K1A 0Y3.

81:6599 Maki, Tadashi, Ichiro Kawasaki and Akiko Horie,

1980. Earthquake mechanisms associated with the conjunction of the sinking plates beneath the Kanto District, central Japan. Bull. Earthq. Res. Inst., Univ. Tokyo, 55(3):577-600.

o

Seismic data examination yielded focal mechanisms consistent with the subcrustal collision of the Philippine Sea Plate with the Pacific Plate. Shallow earthquakes (45 km) indicated underthrusting to- ward the northwest at a slight dip angle. Deeper earthquakes (70 km), some distance to the southwest, indicate vertical dip-slip along the downgoing Pacific Plate. Earthquake Res. Inst., Univ. of Tokyo, Japan. (slr)

81:6600 Makropoulos, K.C. and P.W. Burton, 1981. A

catalogue of seismicity in Greece and adjacent areas. Geophys. Jl R. astr. Soc., 65(3):741-762 + 1 microfiche.

Earthquake instrument data for the period 1901- 1978 are subjected to recalculation of source pa- rameters by single and joint epicenter determina- tions; magnitudes are also recalculated in a consis- tent fashion. The homogeneity thus achieved al- lowed better seismic delineation of the areas; numerous earthquakes prior to 1963 underwent considerable relocation in this new catalogue. Seis- mological Lab., Univ. of Athens, Hippokratous 33, Athens, Greece. (sir)

81:6601 Piqu6, Alain, 1981. Northwestern Africa and the

Avalonian Plate: relations during Late Precam- brian and Late Paleozoic time. Geology, geol. Soc. Am., 9(7):319-322.

Recent fieldwork in NW Africa revealed similarities in the structural and tectonic histories of Morocco,