Long-term seismic activity prior to the December 26, 2004, off the west coast of northern Sumatra, Indonesia, MW=9.0 earthquake was investigated using the Harvard CMT catalogue. It is observed that before this great e...Long-term seismic activity prior to the December 26, 2004, off the west coast of northern Sumatra, Indonesia, MW=9.0 earthquake was investigated using the Harvard CMT catalogue. It is observed that before this great earth-quake, there exists an accelerating moment release (AMR) process with the temporal scale of a quarter century and the spatial scale of 1 500 km. Within this spatial range, the MW=9.0 event falls into the piece-wise power-law-like frequency-magnitude distribution. Therefore, in the perspective of the critical-point-like model of earthquake preparation, the failure to forecast/predict the approaching and/or the size of this earthquake is not due to the physically intrinsic unpredictability of earthquakes.展开更多
The coupling numerical model between astronomical tide and tsunamis was built based on the data of the COMCOT model, which was verified by the Japan "3·11" tsunami. The tsunami source of the Manila seis...The coupling numerical model between astronomical tide and tsunamis was built based on the data of the COMCOT model, which was verified by the Japan "3·11" tsunami. The tsunami source of the Manila seismic tsunami was designed and computed to analyze the risk of tsunami which will happen in the Guangdong coast. According to the results, the maximum quantity of water increasing and the time of the tsunami arriving at the Guangdong seacoast were calculated. The coupling simulation between astronomical tide and tsunamis has significant meaning for evaluating the risk and early-warning of tsunamis in the Guangdong coastal area.展开更多
In Tokyo Metropolitan University, the horizontal and vertical array earthquake observations has begun in June 1994 at the five stations （kl-k5） on the ground surface and bedrock （k6：-30 m depth） at Zushi-site. Mo...In Tokyo Metropolitan University, the horizontal and vertical array earthquake observations has begun in June 1994 at the five stations （kl-k5） on the ground surface and bedrock （k6：-30 m depth） at Zushi-site. More than 200 medium and small earthquakes with the magnitude 5.0-7.3 were recorded between 1994 and 2012. At the 2011 off the Pacific coast of Tohoku Earthquake （EQ.3.11 M = 9.0）, the largest surface ground acceleration （kl = 124.5 gal, k6 = 45.5 gal） of the horizontal component was recorded. Main results were obtained as follows： （1） the surface ground motion characteristics of Zushi-site were examined using the observed data （kl ＆ k6） of EQ.3.11, the past-observed smaller earthquakes （EQ.1 ＆ EQ.10.08） and aftershock （EQ.12.3）, respectively. The non-liner seismic response characteristics of the surface ground at Zushi-site were verified during EQ.3.11. （2） The ground structure models were examined and identified by the modal analyses and the FEM （finite element method） identification analyses using the observed acceleration data of EQ.3.11 and the past observed smaller earthquakes. （3） Moreover, the three dimensional seismic response analyses were performed by TDAPUl （time domain 3-dimensional dynamic analysis program）, using k6 for input motions and identified ground structure model, and evaluated the dynamic behaviours of the surface ground. The calculated results agreed well with the observed ones.展开更多
On March 11, 2011, a major earthquake and tsunami occurred in Japan, mainly affecting the Tohoku region and causing a meltdown at the Fukushima Daiichi nuclear power plant. This disaster not only caused great damage t...On March 11, 2011, a major earthquake and tsunami occurred in Japan, mainly affecting the Tohoku region and causing a meltdown at the Fukushima Daiichi nuclear power plant. This disaster not only caused great damage to the affected areas but also had a serious impact on Japanese politics, economy, and society in general. The art field was no exception;Japanese artists began to consider “What art can do?” after the disaster and this question began to be a new theme of Japanese contemporary art. Artists began to find ways to engage with the affected communities, dealing directly with social problems and political issues.展开更多
China’s coastal areas are densely populated,economically developed, and located in close proximity to several potential tsunami sources;therefore, tsunami risk cannot be ignored. This study assessed tsunami risk in c...China’s coastal areas are densely populated,economically developed, and located in close proximity to several potential tsunami sources;therefore, tsunami risk cannot be ignored. This study assessed tsunami risk in coastal areas of China by developing a framework for tsunami risk assessment from the perspectives of hazards,vulnerability, and exposure. First, a probabilistic tsunami hazard assessment(PTHA) model was applied to estimate the potential tsunami sources in both local crustal faults and circum-Pacific subduction zones based on numerical simulations. The output of the PTHA includes tsunami wave height distributions along the coast. Then, an indicator system reflecting exposure and vulnerability to tsunamis in the coastal areas of China was established by using the entropy method and analytic hierarchy process.The PTHA findings show that the tsunami wave height is close to 3 m on the southern coast of the Bohai Sea, the Pearl River Estuary, and the Yangtze River Delta and exceeds 2 m near the Taiwan Strait for the 2000-year return period. The results of the tsunami risk assessment show that the cities at the highest risk level(level I) include Tangshan, Yantai, and Hong Kong, while cities at the high risk level(level II) include Fuzhou, Xiamen, and Quanzhou near the Taiwan Strait and many cities on the Yangtze River Delta, the Pearl River Estuary, and the southern coast of the Bohai Sea. Our findings can provide an understanding of differences in tsunami risk between Chinese coastal cities that may be affected by tsunamis in the future.展开更多
On the 2011 off the Pacific Coast of Tohoku Earthquake, gymnasium buildings exhibited the unexpected structural damages, which prevented a use as evacuation shelters in during- and post-disaster periods. The major fai...On the 2011 off the Pacific Coast of Tohoku Earthquake, gymnasium buildings exhibited the unexpected structural damages, which prevented a use as evacuation shelters in during- and post-disaster periods. The major failure occurr<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ing</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> on the connection between the RC column top and steel roof as well as the cracks in the RC column base w</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">as</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> observed during the emergent inspection. According to the earlier studies, it was implied that the presence of the slotted hole possibly deteriorates the seismic capacity;however, the length of slotted hole was fixed at a certain value. Facing this concern, this research attempts to clarify the influence of the slotted hole length through a comprehensive parametric study by pushover and seismic response analyses. In conclusion, it has been discovered that the slotted hole deteriorates the seismic capacity for the connection failure up to almost 50% of that without slotted hole. Moreover, the discrepancy of characteristics obtained by the static and dynamic analyses is originated by means of the presence of slotted hole. This slotted hole effect should be noted by structural engineers and researchers to provide the adequate seismic diagnosis and strengthening.</span></span></span>展开更多
基金Ministry of Science and Technology Project (2004CB418406).
文摘Long-term seismic activity prior to the December 26, 2004, off the west coast of northern Sumatra, Indonesia, MW=9.0 earthquake was investigated using the Harvard CMT catalogue. It is observed that before this great earth-quake, there exists an accelerating moment release (AMR) process with the temporal scale of a quarter century and the spatial scale of 1 500 km. Within this spatial range, the MW=9.0 event falls into the piece-wise power-law-like frequency-magnitude distribution. Therefore, in the perspective of the critical-point-like model of earthquake preparation, the failure to forecast/predict the approaching and/or the size of this earthquake is not due to the physically intrinsic unpredictability of earthquakes.
基金sponsored by the Youth Fund Project of the National Natural Science Foundation of China(51509023)the Open-end Fund Project of State Key Laboratory of Hydraulic Engineering Simulation and Safety(HESS-1401)+3 种基金Major Open-end Fund Project of Key Laboratory of South China Sea Rights Protection Technology and Application,State Oceanic Administration(SCS1606)Open-end Fund of Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province(2017SS04)Project supported by South China Sea Branch,State Oceanic Administration for Director of Marine Science and Technology(1417)Key Founding of South China Sea Branch of State Oceanic Administration(180106)
文摘The coupling numerical model between astronomical tide and tsunamis was built based on the data of the COMCOT model, which was verified by the Japan "3·11" tsunami. The tsunami source of the Manila seismic tsunami was designed and computed to analyze the risk of tsunami which will happen in the Guangdong coast. According to the results, the maximum quantity of water increasing and the time of the tsunami arriving at the Guangdong seacoast were calculated. The coupling simulation between astronomical tide and tsunamis has significant meaning for evaluating the risk and early-warning of tsunamis in the Guangdong coastal area.
文摘In Tokyo Metropolitan University, the horizontal and vertical array earthquake observations has begun in June 1994 at the five stations （kl-k5） on the ground surface and bedrock （k6：-30 m depth） at Zushi-site. More than 200 medium and small earthquakes with the magnitude 5.0-7.3 were recorded between 1994 and 2012. At the 2011 off the Pacific coast of Tohoku Earthquake （EQ.3.11 M = 9.0）, the largest surface ground acceleration （kl = 124.5 gal, k6 = 45.5 gal） of the horizontal component was recorded. Main results were obtained as follows： （1） the surface ground motion characteristics of Zushi-site were examined using the observed data （kl ＆ k6） of EQ.3.11, the past-observed smaller earthquakes （EQ.1 ＆ EQ.10.08） and aftershock （EQ.12.3）, respectively. The non-liner seismic response characteristics of the surface ground at Zushi-site were verified during EQ.3.11. （2） The ground structure models were examined and identified by the modal analyses and the FEM （finite element method） identification analyses using the observed acceleration data of EQ.3.11 and the past observed smaller earthquakes. （3） Moreover, the three dimensional seismic response analyses were performed by TDAPUl （time domain 3-dimensional dynamic analysis program）, using k6 for input motions and identified ground structure model, and evaluated the dynamic behaviours of the surface ground. The calculated results agreed well with the observed ones.
文摘On March 11, 2011, a major earthquake and tsunami occurred in Japan, mainly affecting the Tohoku region and causing a meltdown at the Fukushima Daiichi nuclear power plant. This disaster not only caused great damage to the affected areas but also had a serious impact on Japanese politics, economy, and society in general. The art field was no exception;Japanese artists began to consider “What art can do?” after the disaster and this question began to be a new theme of Japanese contemporary art. Artists began to find ways to engage with the affected communities, dealing directly with social problems and political issues.
基金supported by the National Natural Science Foundation of China(Grant No.41771537)the Fundamental Research Funds for the Central Universities。
文摘China’s coastal areas are densely populated,economically developed, and located in close proximity to several potential tsunami sources;therefore, tsunami risk cannot be ignored. This study assessed tsunami risk in coastal areas of China by developing a framework for tsunami risk assessment from the perspectives of hazards,vulnerability, and exposure. First, a probabilistic tsunami hazard assessment(PTHA) model was applied to estimate the potential tsunami sources in both local crustal faults and circum-Pacific subduction zones based on numerical simulations. The output of the PTHA includes tsunami wave height distributions along the coast. Then, an indicator system reflecting exposure and vulnerability to tsunamis in the coastal areas of China was established by using the entropy method and analytic hierarchy process.The PTHA findings show that the tsunami wave height is close to 3 m on the southern coast of the Bohai Sea, the Pearl River Estuary, and the Yangtze River Delta and exceeds 2 m near the Taiwan Strait for the 2000-year return period. The results of the tsunami risk assessment show that the cities at the highest risk level(level I) include Tangshan, Yantai, and Hong Kong, while cities at the high risk level(level II) include Fuzhou, Xiamen, and Quanzhou near the Taiwan Strait and many cities on the Yangtze River Delta, the Pearl River Estuary, and the southern coast of the Bohai Sea. Our findings can provide an understanding of differences in tsunami risk between Chinese coastal cities that may be affected by tsunamis in the future.
文摘On the 2011 off the Pacific Coast of Tohoku Earthquake, gymnasium buildings exhibited the unexpected structural damages, which prevented a use as evacuation shelters in during- and post-disaster periods. The major failure occurr<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ing</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> on the connection between the RC column top and steel roof as well as the cracks in the RC column base w</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">as</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> observed during the emergent inspection. According to the earlier studies, it was implied that the presence of the slotted hole possibly deteriorates the seismic capacity;however, the length of slotted hole was fixed at a certain value. Facing this concern, this research attempts to clarify the influence of the slotted hole length through a comprehensive parametric study by pushover and seismic response analyses. In conclusion, it has been discovered that the slotted hole deteriorates the seismic capacity for the connection failure up to almost 50% of that without slotted hole. Moreover, the discrepancy of characteristics obtained by the static and dynamic analyses is originated by means of the presence of slotted hole. This slotted hole effect should be noted by structural engineers and researchers to provide the adequate seismic diagnosis and strengthening.</span></span></span>
