Recent developments in seismically isolated buildings in Japan     

Shin Okamoto  Nagahide Kani  Masahiko Higashino  Norihide Koshika  Masayuki Kimizuka  Mitsumasa Midorikawa  Masanori Iiba 《地震工程与工程振动(英文版)》2002,1(2):213-225

The Building Standard Law of Japan and related Enforcement Order and Notifications have been substantially revised since the year 2000 to introduce a performance-based regulatory and deregulation system for building control systems. Up to then, time-history analyses were mandatory for isolated buildings and had to be specially approved by the Minster of the Ministry of Construction (MOC). Simplified design procedures based on the equivalent linear method for seismically isolated buildings have been issued as “Notification 2009 — Structural calculation procedure for buildings with seismic isolation” from MOC, and are now integrated into the Ministry of Land, Infrastructure, and Transportation (MLIT). Along with Notification 2009, “Notification 1446 of year 2000 — Standard for specifications and test methods for seismic isolation devices” was also issued. Buildings with heights equal to or less than 60m and that are designed according to these Notifications, including base isolated buildings, only need approval from local building officials, and no longer require the special approval of the Minister of MLIT. This paper summarizes: 1) some statistics related to buildings with seismic isolation completed up to the end of 2001; 2) simplified design procedures required by Notification 2009 of year 2000; and 3) performance of seismic isolation devices required by Notification 1446 of year 2000.  相似文献   

Palaeoecology and biostratigraphy of early Cretaceous (Aptian) calcareous nannofossils and the δC_carb isotope record from NE Iran     

Azam Mahanipour  Jörg MutterloseAnoshiravan L. Kani  Mohammad Hosein Adabi 《Cretaceous Research》2011,32(3):331-356

Upper Barremian-Lower Aptian sediments of the Sarcheshmeh and Sanganeh formations in the Kopet Dagh area, northeast Iran were studied with regard to their calcareous nannofossil content and their δ¹³C_carb signal. The sediments are composed mainly of marlstones, argillaceous limestones and limestones. Based on the occurrence of biostratigraphic index taxa, the calcareous nannofossil zones NC5, NC6 and the NC7A Subzone were recognised. The calcareous nannofossils and the δ¹³C_carb data enable recognition of the early Aptian Oceanic Anoxic Event 1a (OAE 1a). The deposits of the OAE 1a interval are characterised by the rarity of nannoconids and a sharp negative δ¹³C_carb excursion (1.36‰), followed by an abrupt positive δ¹³C_carb excursion of 4-5‰; both events have been recognised elsewhere in OAE 1a deposits in the Tethys. In the OAE 1a interval, the relative abundance of Watznaueria barnesiae/Watznaueria fossacincta is higher (more than 40%) than that of Biscutum spp., Discorhabdus spp. and Zeugrhabdotus spp., which indicates dissolution. In the upper part of the section, the higher relative abundance of mesotrophic and oligotrophic taxa (Watznaueria spp. and nannoconids respectively) and the enhanced relative abundance of eutrophic taxa (Biscutum spp., Discorhabdus spp., Zeugrhabdotus spp.) is indicative of an environment with slightly increased nutrient content. The presence of warm water taxa (Rhagodiscus asper and nannoconids) and the absence of cool water taxa (Repagulum and Crucibiscutum) suggest warm surface-water conditions.  相似文献   

Isotopic geochemistry of Hualalai shield-stage tholeiitic basalts from submarine North Kona region,Hawaii     

Seiko Yamasaki  Tomomi Kani  Barry B. Hanan  Takahiro Tagami 《Journal of Volcanology and Geothermal Research》2009

The geochemical data of Hualalai tholeiitic basalts allow extension of the temporal variations established at Mauna Loa back in time, and provide important information for the long-term temporal variation of the Hawaiian lavas. We report new Hf, Pb, Nd, and Sr isotope compositions for 32 Hualalai tholeiitic basalts collected from deep submarine portions of the North Kona region. The samples were collected from the lower section of the North Kona bench (dives K218 and K219), a submarine stratigraphic section at Hualalai volcano's northwest rift zone (dive S690), and an elongate ridge outboard of the central section of the bench (dive S692), during two JAMSTEC Hawaii cruises in 2001 and 2002. The Hualalai shield-stage tholeiitic basalts have magma source isotopic signatures similar to Mauna Loa. The new data shows temporal Pb and Sr isotope trends that correspond to the long-term temporal variations in Loa-trend lavas, and the Hualalai–Mauna Loa lavas seem to show inter-shield geochemical excursions. Variation in Pb and Sr isotopes at Hualalai appears to take place over a longer time scale than at Mauna Loa. The merged Hualalai–Mauna Loa isotopic trends support models where heterogeneous material in the plume conduit is distributed chaotically, with variable cross-sectional density and length scale.  相似文献