163 research outputs found
Delamination structure imaged in the source area of the 1982 Urakawa-oki earthquake
Get PDFThe Kuril arc collides with the northeast Japan arc in the southern part of Hokkaido, Japan. 3-D tomographic inversion of data from a dense network of sensitive ocean-bottom seismographs and land stations has allowed imaging of previously unseen details of the arc-arc collision structure. A low velocity body dips gently southwestward, at depths of 35 to 45 km, from east of the Hidaka Mountains to the source area of the 1982 Urakawa-oki destructive earthquake (Ms 6.8). The low velocity body is the lower half of the lower crust of the Kuril arc, which must have been delaminated by the collision. We believe that the continuing collision of the delaminated lower crust with the northeast Japan arc resulted as an episode of aseismic slow slip prior to the 1982 Urakawa-oki earthquake as well being the reason for the high seismic activity in this region
RE-DESIGN TEMPAT WISATA DANAU TELUK GELAM, KABUPATEN OKI SUMATERA SELATAN
Get PDFTeluk Gelam Lake Area, OKI Regency is a tourist area that is quite a lot of interest by the OKI population compared with other tourist attractions in OKI District. It's just that this tourist spot is in the planning of the re-design done by the regent of OIC caused by the use of inappropriate places, the arrangement of the far between the masses, the lack of facilities so that the reduced number of tourists coming for it the author took the title "Re-Design Place Wisata Danau Gelam, OKI ". In the re-design of this sights, the authors emphasize the core of the building and the arrangement that can attract the interest of tourists so that the theme applied in this Gelam Lake Tourist Site is the atomic theme with the concept of trajectory and atomic structure while the atmosphere of the tourist attractions is a recreational atmosphere. Hopefully that the relationship between atomic concept and atmosphere in area can create a warm and recreational atmosphere for visitors. The inter-theme, concept and atmosphere application is embodied in the building through postmodern forms of neo-vernacular style
Stress adjustment revealed by seismicity and earthquake focal mechanisms in northeast China before and after the 2011 Tohoku-Oki earthquake
No full textIn order to understand the influence of the March 11, 2011, M-w 9.0 Tohoku-Oki earthquake on regional-scale seismicity, we study the seismicity rate and focal mechanism solutions (FMSs) of earthquakes in northeast China (NEC) before and after the megathrust event. Broadband seismic waveforms from 270 permanent and temporary stations are used to invert for the moment tensors of 69 earthquakes between 2009 and 2013 in the NEC. Our results show that there are distinct changes in seismicity rate on major NEC faults before and after the 2011 Tohoku-Oki event although the seismic moment rate of the whole region remains roughly constant. In comparison to a wide distribution of earthquakes before the Tohoku-Oki event, FMSs of crustal earthquakes in the NEC after the megathrust event can be categorized into two groups: strike-slip events with E-W compression and normal-faulting events with N-S extension. Stress field inversions before and after the Tohoku-Oki event suggest that the variations in seismicity and FMSs are due to a minor adjustment of regional stress state imposed by the megathrust event, which is further confirmed by static Coulomb stress change calculations. Mantle-depth seismicity is also influenced by the megathrust event, possibly via a down-dip transfer of compressional stress along the subducting plate, as manifested by the absence of moderate-sized mantle depth earthquakes (similar to Mw 4-5) between May 2011 and April 2013 and the occurrence of deep-focus events with P axes along the dip direction of the subducting Pacific Plate in E-W vertical cross-sectional view and in WNW-ESE direction in map view. (C) 2015 Elsevier B.V. All rights reserved.National Science Foundation of China [41130316]SCI(E)[email protected]
Damage to Steel Buildings Observed after the 2011 Tohoku-Oki Earthquake
Get PDFA joint U.S.-Japan reconnaissance team examined the damage to steel building structures caused by the 2011 Tohoku-oki earthquake. In the city of Sendai, where the peak horizontal ground acceleration exceeded 1 g, the majority of steel buildings performed well. Buildings that used older cladding systems for external finish sustained damage to their claddings even if their structural performance was excellent. Damage to a few braced frames offer insight into the seismic design of bracing connections. In areas attacked by the violent tsunami, many steel buildings stood upright after the tsunami subsided, although these buildings lost much of their external and internal finishes along with their contents. These steel buildings did not provide safe shelter for tsunami evacuation when the building submerged under the tsunami wave. A number of buildings suffered foundation failure, which was likely caused by scouring or liquefaction or a combination of multiple effects
Observing coseismic gravity change from the Japan Tohoku-Oki 2011 earthquake with GOCE gravity gradiometry
No full textThe Japan Tohoku-Oki earthquake (9.0 Mw) of 11 March 2011 has left signatures in the Earth's gravity field that are detectable by data of the Gravity field Recovery and Climate Experiment (GRACE) mission. Because the European Space Agency's (ESA) satellite gravity mission Gravity field and steady-state Ocean Circulation Explorer (GOCE)—launched in 2009—aims at high spatial resolution, its measurements could complement the GRACE information on coseismic gravity changes, although time-variable gravity was not foreseen as goal of the GOCE mission. We modeled the coseismic earthquake geoid signal and converted this signal to vertical gravity gradients at GOCE satellite altitude. We combined the single gradient observations in a novel way reducing the noise level, required to detect the coseismic gravity change, subtracted a global gravity model, and applied tailored outlier detection to the resulting gradient residuals. Furthermore, the measured gradients were along-track filtered using different gradient bandwidths where in the space domain Gaussian smoothing has been applied. One-year periods before and after earthquake occurrence have been compared with the modeled gradients. The comparison reveals that the earthquake signal is well above the accuracy of the vertical gravity gradients at orbital height. Moreover, the obtained signal from GOCE shows a 1.3 times higher amplitude compared with the modeled signal. Besides the statistical significance of the obtained signal, it has a high spatial correlation of ~0.7 with the forward modeled signal. We conclude therefore that the coseismic gravity change of the Japan Tohoku-Oki earthquake left a statistically significant signal in the GOCE measured gravity gradients.Geoscience & Remote SensingCivil Engineering and Geoscience
Atmospheric gravity waves due to the Tohoku-Oki tsunami observed in the thermosphere by GOCE
Get PDFInternational audienceOceanic tsunami waves couple with atmospheric gravity waves, as previously observedthrough ionospheric and airglow perturbations. Aerodynamic velocities and density variations are computed from Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) accelerometer and thruster data during Tohoku-Oki tsunami propagation. High-frequency perturbations of these parameters are observed during three expected crossings of the tsunami-generated gravity waves by the GOCE satellite. From theoretical relations between air density and vertical and horizontal velocities inside the gravity wave, we demonstrate that the measured perturbations are consistent with a gravity wave generated by the tsunami and provide a way to estimate the propagation azimuth of the gravity wave. Moreover, because GOCE measurements can constrain the wave polarization, a marker (noted C 3 ) of any gravity wave crossing by the GOCE satellite is constructed from correlation coefficients between the observed atmospheric state parameters. These observations validate a new observation tool of thermospheric gravity waves generated by tsunamis above the open ocean
Late Cenozoic Tectono-Sedimentary History in the Oki-Dogo Island, and its Implication for the Origin of Topographic and Structural Relief in the Southwestern Japan Sea
Get PDFThe Japan Sea is a marginal basin formed through backarc basin opening during the early to middle Miocene. It is composed of topographic depressions (basin) and highs (ridge, sea mount and rise) and shows obvious large topographic irregularities. The crust of marginal basin is understood to be a mosaic consisting of fragmental continental crust, rifted continental crust, extended continental crust, and newborn oceanic crust. The crust of Oki-Dogo Island, which in one of the topographic high in the southwestern Japan Sea, is considered to be a fragmental continental crust without marked disturbances during the opening process of the backarc basin.
In the Oki-Dogo Island, a thick series of Tertiary and Quaternary strata have developed covering unconformably the crystalline basements. They are classified into the following five groups: the upper Oligocene to lowermost Lower Miocene Tokibariyama Formation, the Lower to Middle Miocene Dogo Group, the uppermost Upper Miocene Oki Group, the Pliocene Omine Group, and the Pleistocene Saigo Group and Holocene Nijiyama Gravel Beds. They form structural association of dome and graben structures.
The Tokibariyama Formation, mostly composed of talc-alkaline volcanics, was deposited in relation to the formation of Tokibariyama cauldron located on the Oligocene volcanic front. The Dogo Group was deposited in and around the Dogo graben which is closely connected to the Japan Sea rifting. It is made up of alkali basalts (shoshonite) and acid pyroclastics in the lower part, and of the clastic and biosiliceous sediments deposited in the paralic and shallow and deep-marine environments, in the upper part. The Oki Group closely related to the formation of the Tsuzuraoyama dome structure is represented by thick piles of subaerial felsic alkaline volcanic rocks with small amount of shallow marine elastics in the lowermost part. The Omine Group forms monogenetic volcanoes which mostly consist of alkali basalts with mafic and ultramafic xenoliths erupted on the Fuse tilted block, tilting gently toward northwest in the northeastern part of the island. The Saigo Group is composed of alkali basalts and the Nijiyama Gravel Beds consist of terrace deposits. They are distributed in the limited area of the souththern part of the island.
According to the tectono-sedimentary history reconstructed by the author, the Oki-Dogo area has experienced the continental-arc type volacanism of the latest Oligocene to earliest Miocene age, and the rifting with bimodal volcanism and subsequent subsidence, down to middle bathyal zone of early Early to Middle Miocene age. These processes are characteristic of the rifted and the extended continental crusts in tha Japan Sea. Since the Late Miocene, the three-step successive tectono-magmatic uplifting processes have transformed the Oki-Dogo area into an island which projects above the sea surface.
In conclusion, the Oki-Dogo Island is not a simple piece of continental crust that fragmented through the opening process of the Japan Sea, but the results of a complex evolutionary process, which involves the earlier rifting and deep subsidence followed later on by tectono-magmatic uplifting. Such multi-phased and superimposed formative porcesses of the Oki-Dogo Island may imply that various structural highs in the Japan Sea also have their respective evolutional histories, and that tectono-sedimentary histories should be individually reconstructed to elucidate the origins of topographic and structural highs. Correlations between the variation in the character of volcanism and tectonic events can be due to changes in the tectonic status of the crust
Local variation of inundation, sedimentary characteristics, and mineral assemblages of the 2011 Tohoku-oki tsunami on the Misawa coast, Aomori, Japan
Get PDFThe 2011 Tohoku-oki tsunami caused severe damage to the coastal regions of eastern Japan and left a sediment veneer over affected areas. We discuss differences in depositional characteristics of the 2011 Tohoku-oki tsunami from the viewpoint of the sediment source, coastal topography and flow height. The study area on the Misawa coast, northern Tohoku, includes a 20 km long coastline with sandy beaches, coastal dunes and a gently sloping lowland. This landscape assemblage provides an opportunity to examine the effects of topography on the characteristics of the tsunami deposit. During field surveys conducted from April 10 to May 2, 2011, we described the thickness, facies, and structure of the tsunami deposit. We also collected sand samples at approximately 20 m intervals along 13 shore-perpendicular transects extending up to 550 m inland, for grain size and mineral assemblage analysis. The tsunami flow height was estimated by measuring the elevation of debris found in trees, broken tree limbs, or water marks on buildings. The nature of the coastal lowland affected the flow height and inundation distance. In the southern part of the study area, where there is a narrow, 100 m wide low-lying coastal strip, the run-up height reached 10 m on the landward terrace slopes. To the north, the maximum inundation reached 550 m with a run-up height of 32 m on the wider, low-lying coastal topography. The average flow height was 4-5 m. The tsunami eroded coastal dunes and formed small scarps along the coast. Immediately landward of the coastal dunes the tsunami deposit was more than 20 cm thick, but thinned markedly inland from this point. Close to the dunes the deposit was composed largely of medium sand (1-2 Φ) with planar and parallel bedding, but with no apparent upward fining or coarsening. The particle size was similar to that of the coastal dune and we infer that the dunes were the local source material for the tsunami deposit at this point. The mineral assemblage of the tsunami deposit was dominated by orthopyroxene and clinopyroxene and was also similar to the dune and beach sand. At sites more than half the inundation distance inland, the thinner tsunami deposit consisted mainly of fine sand (2.375 Φ) with some upward fining. The difference in particle size and sedimentary characteristics was probably caused by differences in sediment transportation and depositional processes. We infer that the well-sorted, finer sediments were deposited out of suspension, whereas the relatively coarse sands were laid down from traction flows. The depositional characteristics of the 2011 Tohoku-oki tsunami deposit appeared to have been affected mainly by the coastal topography and the extent of erosion at any one point, as opposed to flow height
State4: State-preserving Reconfiguration of P4-programmable Switches
No full textTo cater to constantly changing network needs, enabling stateful reconfiguration of Network Functions (NFs) is crucial. Recently, there has been growing interest in offloading NFs to programmable network devices. Unfortunately, it is currently not possible to maintain the full state of NFs during a switch reconfiguration without consuming network resources from and to neighboring switches. In this paper, we present State4, a framework that maintains the state of P4 programs during the reconfiguration of a P4-programmab1e network device, by only using a small amount of local resources on the switch undergoing reconfiguration. State4 acts on both the in-switch control-plane and the data-plane. By utilizing the in-switch local controller, State4 requires no external network resources to achieve reconfiguration while preserving states. As such, State4 enables on-The-fly reconfiguration of stateful NFs, at minimal traffic disruption, where previously traffic had to be re-routed.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Networked System
A Preliminary Survey of the River Trade in Central and South Sumatra in the 19th Century: A Viewpoint of the Trade Structure of Southeast Asia
Get PDFこの論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。The Malacca Strait figured as an entrepot for the international trade of Southeast Asia up until recent times because its location was suitable for the East-West trade covering Europe and the Arab and Indian worlds on one hand, and China and Japan on the other. Since trade was a significant economic basis for political power, it has been one of the major themes in the history of Southeast Asia. Historians have traditionally studied the international trade around the Malacca Strait focusing on the sea route and overseas trade. However, this approach is not sufficient to fully understand the structure of the international trade, particularly when we consider such problems as how commodities were brought to international ports, or how imported commodities were distributed from these ports. These questions are especially important for Central and South Sumatra where export goods were mainly produced inland and imported goods were also consumed inland. This paper attempts to describe the trade structure in Central and South Sumatra, paying attention to rivers as trade routes, which so far have been studied very little. These rivers include the Siak, Kampar, Kuantan-Indragiri, Batang Hari, and Musi, all of which rise in the Barisan mountain range (stretching north to south parallel to the west coast of Sumatra), and empty into the east coast sea. Because they are navigable by boats (perahu) almost up to their sources, they have been used as trade routes since ancient times. This paper covers the historical background, the navigation of boats, trade, and trade structure of these river routes. The author hopes that this study of river trade, and trade structure of these river routes. The author hopes that this study of river trade will broaden the scope of the economic and political history of Southeast Asia
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