Evidence for pre-seismic crustal movement in China and Japan

Some recent Chinese observations on precursory crustal movements detected by geodetic measurements such as short-range levelling or base-line survey across the active fault corroborate the three gamma phases model of Fujita and Fujii: Gamma 1 phase is pre-slip along the imminent faulting, gamma 2 is coseismic slip and gamma 3 is post-slip along the main or subsidiary faulting after an earthquake. Typical of these are the results of short-range levelling across the earthquake fault that ruptured during the 1976 Tangshan earthquake (M_s= 7.8). Associated with the occurrence of the Tangshan earthquake or the subsequent Ninghe earthquake (M_s= 6.9), remarkable gamma 2 phases were observed. At this same location abnormal gamma 1 or gamma 3 phases were detected from the Lulong 1982 earthquake (M_s= 6.2) that originated from the north end of the Tangshan Fault and was one of the aftershocks of the Tangshan earthquake. These phases are interpreted by analogy with the recent experimental results of stick-slip motion of the frictional sliding of rock.     

Livestock wastes as a source of estrogens and their effects on wildlife of Manko tidal flat,Okinawa

The Manko tidal flat in the southern part of Okinawa Island is an important visiting and wintering area for migratory birds and was added to the Ramsar Convention Register of Wetlands in 1999. This area used to be an inlet extending to the inner part of Naha Port, but recent reclamation projects have restricted its connection to the East China Sea. As is typical in rural regions of subtropical islands, the inhabitants in the Manko basin raise livestock, especially pigs, without employing sufficient waste treatment methods. As sewage treatment works are considered to be one of the main sources of environmental estrogens in urban areas, the significance of livestock farming as a source of estrogens in rural area is examined in this study. In the present study, total estrogenic activities in water and sediment samples from the Manko tidal flat and its basin were measured using a recombinant yeast screen method. Estrogenic activities (equivalent to 17beta-estradiol, E2) were around 10 ng l(-1) in water samples and more than 10 microg kg(-1) in some sediment samples. In addition, the concentrations of estrone (E1) and E2 in water samples measured using LC/MS/MS indicated a high contribution of environmental estrogens from livestock wastes.     

The petrology of ultramafic xenoliths from Summit Lake,near Prince George,British Columbia

Approximately 200 upper mantle xenoliths from Summit Lake, near Prince George, British Columbia, were collected from a basanitoid flow of Late Cenozoic (possibly post-glacial) age. The most abundant xenolith is spinel lherzolite (55%), with subordinate wehrlite (22%), clinopyroxenite (10%), olivine websterite (10%), websterite (2%) and dunite (1%). Xenoliths have granular textures and both green chrome diopside-bearing and black aluminous augitebearing xenoliths are present. About 5% of the xenoliths are banded on a cm scale, suggesting that the upper mantle beneath north-central British Columbia is heterogeneous on a scale of cm to meters.Microprobe data on the mineral phases indicate that the xenoliths are generally well equilibrated. Typically in spinel lherzolite, olivines are Fo₈₉, orthopyroxenes are En₉₀ and chrome diopside is Wo₄₅En₅₀Fs₅. Spinels vary in composition from xenolith to xenolith. The evidence for partial melting observed in five xenoliths, may be due to heating during incorporation of the xenoliths within the host magma or to instability caused by decompression as the xenoliths are transported to the surface.Using element partition geothermometers, equilibration temperatures are calculated to be between 1080–1100° C. Pressures, estimated from a Cordilleran geotherm, are between 18–20 kbar. These temperatures are somewhat higher than estimates from xenoliths from other localities in Late Cenozoic alkali basalts in south and central British Columbia. It is concluded, therefore, that either the Summit Lake suite represents samples from a deeper source region in the upper mantle or the Late Cenozoic geotherm varied in time and space.On leave from the Geological Institute, University of Tokyo