Precursory Activation of Seismicity in Advance of the Kobe, 1995, M = 7.2 Earthquake     

V. G. Kossobokov  K. Maeda  S. Uyeda 《Pure and Applied Geophysics》1999,155(2-4):409-423

—A succession of precursory changes of seismicity characteristic to earthquakes of magnitude 7.0–7.5 occurred in advance of the Kobe 1995, M = 7.2, earthquake. Using the Japan Meteorological Agency (JMA) regional catalog of earthquakes, the M8 prediction algorithm (Keilies-Borko and Kossobokov, 1987) recognizes the time of increased probability, TIP, for an earthquake with magnitude 7.0–7.5 from July 1991 through June 1996. The prediction is limited to a circle of 280-km radius centered at 33.5°N, 133.75°E. The broad area of intermediate-term precursory rise of activity encompasses a 175 by 175-km square, where the sequence of earthquakes exhibited a specific intermittent behavior. The square is outlined as the second-approximation reduced area of alarm by the "Mendocino Scenario" algorithm, MSc (Kossobokov et al., 1990). Moreover, since the M8 alarm starts, there were no swarms recorded except the one on 9–26 Nov. 1994, located at 34.9°N, 135.4°E. Time, location, and magnitude of the 1995 Kobe earthquake fulfill the M8-MSc predictions. Its aftershock zone ruptured the 54-km segment of the fault zone marked by the swarm, directly in the corner of the reduced alarm area. The Kobe 1995 epicenter is less than 50 km from the swarm and it coincides with the epicenter of the M 3.5 foreshock which took place 11 hours in advance.  相似文献   

Notes　on　Extended-Range　Atmospheric　Prediction　in　the　Northern　Hemisphere　Winter     

Shingo Yamada Forecast Division  Japan Meteorological Agency  Tokyo    Japan Shuhei Maeda Administration Division  Climate  Marine Department  Japan Meteorological Agency  Tokyo    Japan K. Gambo c/o Department of Earth  Planetary Physi 《大气科学进展》1997,(1)

ＮｏｔｅｓｏｎＥｘｔｅｎｄｅｄ－ＲａｎｇｅＡｔｍｏｓｐｈｅｒｉｃＰｒｅｄｉｃｔｉｏｎｉｎｔｈｅＮｏｒｔｈｅｒｎＨｅｍｉｓｐｈｅｒｅＷｉｎｔｅｒＳｈｉｎｇｏＹａｍａｄａＦｏｒｅｃａｓｔＤｉｖｉｓｉｏｎ，ＪａｐａｎＭｅｔｅｏｒｏｌｏｇｉｃａｌＡｇｅｎｃｙ...  相似文献   

Estimation of Response Spectra in the Severely Damaged Area During the 1995 Hyogo-Ken Nambu Earthquake     

Sato  Tadanobu  Kita  Katsutoshi  Maeda  Tomonari 《Natural Hazards》1997,16(2-3):203-218

We calculated theoretical acceleration response spectra at the ground surface in the region near the 1995 Hyogo-ken Nambu earthquake source based on the spectral moment method. To estimate earthquake motion on the ground surface, a formula of earthquake motion at base rock level was derived. The amplification effect of the ground was introduced by using multiple reflection theory. Theoretically estimated response spectrum were modified by the response spectra calculated using observed earthquake motions.  相似文献   

G-3 Technology of wave energy utilization     

Hisaaki Maeda 《Ocean Engineering》1985,12(6):547-548

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The Role of Suspended Oyster Culture on Nitrogen Cycle in Hiroshima Bay   总被引：1，自引：0，他引：1  

Putth Songsangjinda  Osamu Matsuda  Tamiji Yamamoto  Narasimmalu Rajendran  Hajime Maeda 《Journal of Oceanography》2000,56(2):223-231

The predominance of bivalves affects the cycle of materials in the coastal ecosystem. In the present study, the role of suspended oyster culture on the nitrogen cycle was demonstrated for the northern Hiroshima Bay. The nitrogen cycle was considered as two systems, (1) the primary production (PP) system and (2) the oyster culture (OC) system. The results show that about 26% of N productivity was supplied to process by cultured oysters in the OC system. This process varies seasonally due to the seasonal variations of PON, physiological activities and biomass of oysters. The N processing rates were found to be high in summer and low in winter. The biodeposition and excretion of N in the OC system are 3.0 and 2.1 ton N d^–1, while the natural sedimentation rate and N regeneration in the PP system are 8.3 and 18.0 ton N d^–1, which indicates that the PP system is a major system regenerating N in the water column. The release of total dissolved N from the bottom to the water column is about 8.3 ton N d^–1. The amount of N harvested as oyster product was about 1.3 ton N d^–1, which is about 10% of daily N loading in north Hiroshima Bay. According to the N cycle developed in the present study, the results suggest the significant role of suspended oyster culture on the nitrogen cycle in Hiroshima Bay. In addition, our results indicate that oyster production was efficiently harvested, suggesting that oyster culture could probably be used as a tool to remove N from Hiroshima Bay.  相似文献   

FDM Simulation of an Anomalous Later Phase from the Japan Trench Subduction Zone Earthquakes     

Shinako Noguchi  Takuto Maeda  Takashi Furumura 《Pure and Applied Geophysics》2013,170(1-2):95-108

We investigated the development of a distinct later phase observed at stations near the Japan Trench associated with shallow, outer-rise earthquakes off the coast of Sanriku, northern Japan based on the analysis of three-component broadband seismograms and FDM simulations of seismic wave propagation using a heterogeneous structural model of the Japan Trench subduction zone. Snapshots of seismic wave propagation obtained through these simulations clearly demonstrate the complicated seismic wavefield constructed by a coupling of the ocean acoustic waves and the Rayleigh waves propagating within seawater and below the sea bottom by multiple reflections associated with shallow subduction zone earthquakes. We demonstrated that the conversion to the Rayleigh wave from the coupled ocean acoustic waves and the Rayleigh wave as they propagate upward along the slope of seafloor near the coast is the primary cause of the arrival of the distinct later phase at the station near the coast. Through a sequence of simulations using different structural models of the Japan Trench subduction zone, we determined that the thick layer of seawater along the trench and the suddenly rising sea bottom onshore of the Japanese island are the major causes of the distinct later phase. The results of the present study indicate that for realistic modeling of seismic wave propagation from the subduction zone earthquakes, a high-resolution bathymetry model is very crucial, although most current simulations do not include a water column in their simulation models.  相似文献   

Paleoecology of Inoceramus amakusensis Nagao et Matsumoto, 1940 (Bivalvia) in a Late Cretaceous shallow clastic sea: The Himenoura Group, Kyushu, Japan     

Taro Kumagae  Haruyoshi Maeda  Toshifumi Komatsu 《Cretaceous Research》2011,32(6):738-749

The taphonomic features and paleoecology of this species were investigated focused on vertically embedded individuals of articulated Inoceramus amakusensis Nagao et Matsumoto. In the Hinoshima Formation, Himenoura Group of Kyushu, Japan, this Santonian (Late Cretaceous) inoceramid bivalve characteristically occurs in incised-valley fill siliciclastic marine deposits. Modes of I. amakusensis occurrence and preservation, from in situ (= occurrence in life position) to allochthonous shell fragments, are strongly affected by its paleoecology and depositional environments. Several I. amakusensis (up to 25 cm in shell height) were recovered from bioturbated sandstones associated with storm-influenced deposits. Their commissural planes are almost perpendicular to the bedding plane, with the anterior face oriented downward and the posteroventral portion extending upward. Furthermore, I. amakusensis is morphologically comparable to endobyssate mytilid bivalves today. These results suggest that this Cretaceous species was an orthothetic sand sticker at least during mid-ontogeny that preferentially inhabited a well-oxygenated, nearshore seafloor. I. amakusensis was distributed in various depositional environments and has been regarded as a recliner in offshore muddy substrate. However, the present discovery suggests that it was also well adapted, with an upright life position, to high-energy shallow clastic environments characterized by high sediment supply.  相似文献   

Dynamic modeling of forest conversion: Simulation of past and future scenarios of rural activities expansion in the fringes of the Xingu National Park,Brazilian Amazon     

Eduardo E. Maeda  Cláudia Maria de Almeida  Arimatéa de Carvalho Ximenes  Antonio R. Formaggio  Yosio E. Shimabukuro  Petri Pellikka 《International Journal of Applied Earth Observation and Geoinformation》2011

The present work is committed to simulate the expansion of agricultural and cattle raising activities within a watershed located in the fringes of the Xingu National Park, Brazilian Amazon. A spatially explicit dynamic model of land cover and land use change was used to provide both past and future scenarios of forest conversion into such rural activities, aiming to identify the role of driving forces of change in the study area. The employed modeling platform – Dinamica EGO – consists in a cellular automata environment that embodies neighborhood-based transition algorithms and spatial feedback approaches in a stochastic multi-step simulation framework. Biophysical variables and legal restrictions drove this simulation model, and statistical validation tests were then conducted for the generated past simulations (from 2000 to 2005), by means of multiple resolution fitting methods. Based on optimal calibration of past simulations, future scenarios were conceived, so as to figure out trends and spatial patterns of forest conversion in the study area for the year 2015. In all simulated scenarios, pasturelands remained nearly stable throughout the analyzed period, while a large expansion in croplands took place. The most optimistic scenario indicates that more than 50% of the natural forest will be replaced by either cropland or pastureland by 2015. This modeling experiment revealed the suitability of the adopted model to simulate processes of forest conversion. It also indicates its possible further applicability in generating simulations of deforestation for areas with expanding rural activities in the Amazon and in tropical forests worldwide.  相似文献   

New buoy observation system for tsunami and crustal deformation     

Narumi Takahashi  Yasuhisa Ishihara  Hiroshi Ochi  Tatsuya Fukuda  Jun’ichiro Tahara  Yosaku Maeda  Motoyuki Kido  Yusaku Ohta  Katsuhiko Mutoh  Gosei Hashimoto  Satoshi Kogure  Yoshiyuki Kaneda 《Marine Geophysical Researches》2014,35(3):243-253

We have developed a new system for real-time observation of tsunamis and crustal deformation using a seafloor pressure sensor, an array of seafloor transponders and a Precise Point Positioning (PPP ) system on a buoy. The seafloor pressure sensor and the PPP system detect tsunamis, and the pressure sensor and the transponder array measure crustal deformation. The system is designed to be capable of detecting tsunami and vertical crustal deformation of ±8 m with a resolution of less than 5 mm. A noteworthy innovation in our system is its resistance to disturbance by strong ocean currents. Seismogenic zones near Japan lie in areas of strong currents like the Kuroshio, which reaches speeds of approximately 5.5 kt (2.8 m/s) around the Nankai Trough. Our techniques include slack mooring and new acoustic transmission methods using double pulses for sending tsunami data. The slack ratio can be specified for the environment of the deployment location. We can adjust slack ratios, rope lengths, anchor weights and buoy sizes to control the ability of the buoy system to maintain freeboard. The measured pressure data is converted to time difference of a double pulse and this simple method is effective to save battery to transmit data. The time difference of the double pulse has error due to move of the buoy and fluctuation of the seawater environment. We set a wire-end station 1,000 m beneath the buoy to minimize the error. The crustal deformation data is measured by acoustic ranging between the buoy and six transponders on the seafloor. All pressure and crustal deformation data are sent to land station in real-time using iridium communication.  相似文献   

Spatiotemporal characterization of land surface temperature in Mount Kilimanjaro using satellite data     

Eduardo Eiji Maeda  Pekka Hurskainen 《Theoretical and Applied Climatology》2014,118(3):497-509

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