The paper considers a catastrophic event-the eruption of Hunga Tonga-Hunga Ha’apai volcano on January 15,2022.The process of preparation and eruption of Hunga Tonga volcano generated tsunami waves that were observed ...The paper considers a catastrophic event-the eruption of Hunga Tonga-Hunga Ha’apai volcano on January 15,2022.The process of preparation and eruption of Hunga Tonga volcano generated tsunami waves that were observed throughout the World Ocean.This event was notable for its unprecedented global impact and the early appearance of tsunami waves at distant coastal stations.So,the first waves at tide gauge stations in Chile and Peru were recorded 4 hours earlier than the arrival time of tsunami waves to the tide gauge after the eruption of Tonga volcano.Two mechanisms are possible for the generation of early tsunami waves:acoustic Lamb waves generated by a volcanic explosion and submarine landslides that occurred on the slopes of the volcano during the preparatory phase of the eruption.In this study,numerical simulation of various pre-eruption landslide scenarios on the slope of Hunga Tonga volcano is carried out in an attempt to explain these early tsunami waves.Under computation the elastoplastic model of landslide was taken into account.Wave characteristics of a tsunami on the coast of Chile and Peru generated by a landslide process on a volcanic slope are obtained.A detailed comparison of virtual tide gauge data with observational ones is used to validate this model.The results obtained can be used to improve early warning systems.展开更多
On April 3,2024,a magnitude Mw 7.4 earthquake struck the city of Hualien,Taiwan,China,causing casualties and immense damage.This earthquake triggered a tsunami,which was recorded by the nearby tide gauges and Deep-Oce...On April 3,2024,a magnitude Mw 7.4 earthquake struck the city of Hualien,Taiwan,China,causing casualties and immense damage.This earthquake triggered a tsunami,which was recorded by the nearby tide gauges and Deep-Ocean Assessment and Reporting of Tsunamis(DART)buoys.These recordings are valuable for evaluating the tsunami source and quantifying the tsunami characteristics.In this study,we conduct tsunami simulations based on three earthquake source models,and analyze their reliability by comparing the computed results with observed waveforms.The evaluated source models are the United States Geological Survey(USGS)finite-fault model,and two uniform slip models using different scaling relations.The tsunami waves generated by each source are simulated with a nonhydrostatic tsunami model,which accounts for the effects of wave dispersion.The computed tsunami arrival times and wave heights are compared to the observed data and show high consistency,indicating that the magnitude and location of the earthquake source are well estimated.Also,the three source models with different rupture area and average slip lead to almost the same tsunami waves at each station,which suggests that earthquake rupture details have limited impact on far-filed tsunami records.It is also found that wave dispersion effects in this event are negligible at most stations.The findings are useful for tsunami warning.For fast warning purposes,it is practically useful to adopt simplified uniform slip models,which are able to predict the tsunami arrival time and wave height relatively well without knowing the earthquake source details.展开更多
Tsunami induced by earthquake is an interaction problem between liquid and solid.Shallow-water wave equation is often used to modeling the tsunami,and the boundary or initial condition of the problem is determined by ...Tsunami induced by earthquake is an interaction problem between liquid and solid.Shallow-water wave equation is often used to modeling the tsunami,and the boundary or initial condition of the problem is determined by the displacement or velocity field from the earthquake under sea floor,usually no interaction between them is consid-ered in pure liquid model.In this study,the potential flow theory and the finite element method with the interaction between liquid and solid are employed to model the dynamic processes of the earthquake and tsunami.For model-ing the earthquake,firstly the initial stress field to generate the earthquake is set up,and then the occurrence of the earthquake is simulated by suddenly reducing the elastic material parameters inside the earthquake fault.It is dif-ferent from seismic dislocation theory in which the relative slip on the fault is specified in advance.The modeling results reveal that P,SP and the surface wave can be found at the sea surface besides the tsunami wave.The surface wave arrives at the distance of 600 km from the epicenter earlier than the tsunami 48 minutes,and its maximum amplitude is 0.55 m,which is 2 times as large as that of the sea floor.Tsunami warning information can be taken from the surface wave on the sea surface,which is much earlier than that obtained from the seismograph stations on land.The tsunami speed on the open sea with 3 km depth is 175.8 m/s,which is a little greater than that pre-dicted by long wave theory,(gh)1/2=171.5 m,and its wavelength and amplitude in average are 32 km and 2 m,respectively.After the tsunami propagates to the continental shelf,its speed and wavelength is reduced,but its amplitude become greater,especially,it can elevate up to 10 m and run 55 m forward in vertical and horizontal directions at sea shore,respectively.The maximum vertical accelerations at the epicenter on the sea surface and on the earthquake fault are 5.9 m/s2 and 16.5 m/s2,respectively,the later is 2.8 times the former,and therefore,sea water is a good shock absorber.The acceleration at the sea shore is about 1/10 as large as at the epicenter.The maximum vertical velocity at the epicenter is 1.4 times that on the fault.The maximum vertical displacement at the fault is less than that at the epicenter.The difference between them is the amplitude of the tsunami at the epicenter.The time of the maximum displacement to occur on the fault is not at the beginning of the fault slipping but retards 23 s.展开更多
Japan＇s first open sea offshore wind farm, Kamisu offshore windfarm Phase l, was stricken by an earthquake of intensity 6 on the Japanese seismic scale and a five-meter-high tsunami during the Great East Japan Earthq...Japan＇s first open sea offshore wind farm, Kamisu offshore windfarm Phase l, was stricken by an earthquake of intensity 6 on the Japanese seismic scale and a five-meter-high tsunami during the Great East Japan Earthquake on March 11,2011. The wind farm resumed operation on March 14 after checks revealed no damage to the system, even though the wind farm was temporarily forced to stop due to the grid failure caused by the earthquake. Wind turbines require a precise seismic design especially in an earthquake-prone country such as Japan. Wind power Kamisu Phase 2 was built one year after the earthquake based on the experience of Kamisu Phase 1. This paper presents the seismic design of offshore wind turbines and the situation during the earthquake and tsunami.展开更多
On February 8,2025,a remote area in the Caribbean Sea was rocked by a large M_(W)7.6(USGS,2025) earthquake,centered 209 km SSW of Georgetown,the capital of the Cayman Islands,and the largest city(population~41 000) of...On February 8,2025,a remote area in the Caribbean Sea was rocked by a large M_(W)7.6(USGS,2025) earthquake,centered 209 km SSW of Georgetown,the capital of the Cayman Islands,and the largest city(population~41 000) of the British Overseas Territories(Figure 1).The earthquake was significant due to its large magnitude,potential regional impact,and the possibility of generating a tsunami.展开更多
基金funded by the Ministry of Science and Higher Education of the Russian Federation(agreement No.075-15-2022-1127 dated July 1,2022).
文摘The paper considers a catastrophic event-the eruption of Hunga Tonga-Hunga Ha’apai volcano on January 15,2022.The process of preparation and eruption of Hunga Tonga volcano generated tsunami waves that were observed throughout the World Ocean.This event was notable for its unprecedented global impact and the early appearance of tsunami waves at distant coastal stations.So,the first waves at tide gauge stations in Chile and Peru were recorded 4 hours earlier than the arrival time of tsunami waves to the tide gauge after the eruption of Tonga volcano.Two mechanisms are possible for the generation of early tsunami waves:acoustic Lamb waves generated by a volcanic explosion and submarine landslides that occurred on the slopes of the volcano during the preparatory phase of the eruption.In this study,numerical simulation of various pre-eruption landslide scenarios on the slope of Hunga Tonga volcano is carried out in an attempt to explain these early tsunami waves.Under computation the elastoplastic model of landslide was taken into account.Wave characteristics of a tsunami on the coast of Chile and Peru generated by a landslide process on a volcanic slope are obtained.A detailed comparison of virtual tide gauge data with observational ones is used to validate this model.The results obtained can be used to improve early warning systems.
基金The National Key R&D Program of China under contract No.2024YFF0506800the National Natural Science Foundation of China under contract No.T2122012.
文摘On April 3,2024,a magnitude Mw 7.4 earthquake struck the city of Hualien,Taiwan,China,causing casualties and immense damage.This earthquake triggered a tsunami,which was recorded by the nearby tide gauges and Deep-Ocean Assessment and Reporting of Tsunamis(DART)buoys.These recordings are valuable for evaluating the tsunami source and quantifying the tsunami characteristics.In this study,we conduct tsunami simulations based on three earthquake source models,and analyze their reliability by comparing the computed results with observed waveforms.The evaluated source models are the United States Geological Survey(USGS)finite-fault model,and two uniform slip models using different scaling relations.The tsunami waves generated by each source are simulated with a nonhydrostatic tsunami model,which accounts for the effects of wave dispersion.The computed tsunami arrival times and wave heights are compared to the observed data and show high consistency,indicating that the magnitude and location of the earthquake source are well estimated.Also,the three source models with different rupture area and average slip lead to almost the same tsunami waves at each station,which suggests that earthquake rupture details have limited impact on far-filed tsunami records.It is also found that wave dispersion effects in this event are negligible at most stations.The findings are useful for tsunami warning.For fast warning purposes,it is practically useful to adopt simplified uniform slip models,which are able to predict the tsunami arrival time and wave height relatively well without knowing the earthquake source details.
基金National Natural Science Foundation of China (40521002 and 40474013).
文摘Tsunami induced by earthquake is an interaction problem between liquid and solid.Shallow-water wave equation is often used to modeling the tsunami,and the boundary or initial condition of the problem is determined by the displacement or velocity field from the earthquake under sea floor,usually no interaction between them is consid-ered in pure liquid model.In this study,the potential flow theory and the finite element method with the interaction between liquid and solid are employed to model the dynamic processes of the earthquake and tsunami.For model-ing the earthquake,firstly the initial stress field to generate the earthquake is set up,and then the occurrence of the earthquake is simulated by suddenly reducing the elastic material parameters inside the earthquake fault.It is dif-ferent from seismic dislocation theory in which the relative slip on the fault is specified in advance.The modeling results reveal that P,SP and the surface wave can be found at the sea surface besides the tsunami wave.The surface wave arrives at the distance of 600 km from the epicenter earlier than the tsunami 48 minutes,and its maximum amplitude is 0.55 m,which is 2 times as large as that of the sea floor.Tsunami warning information can be taken from the surface wave on the sea surface,which is much earlier than that obtained from the seismograph stations on land.The tsunami speed on the open sea with 3 km depth is 175.8 m/s,which is a little greater than that pre-dicted by long wave theory,(gh)1/2=171.5 m,and its wavelength and amplitude in average are 32 km and 2 m,respectively.After the tsunami propagates to the continental shelf,its speed and wavelength is reduced,but its amplitude become greater,especially,it can elevate up to 10 m and run 55 m forward in vertical and horizontal directions at sea shore,respectively.The maximum vertical accelerations at the epicenter on the sea surface and on the earthquake fault are 5.9 m/s2 and 16.5 m/s2,respectively,the later is 2.8 times the former,and therefore,sea water is a good shock absorber.The acceleration at the sea shore is about 1/10 as large as at the epicenter.The maximum vertical velocity at the epicenter is 1.4 times that on the fault.The maximum vertical displacement at the fault is less than that at the epicenter.The difference between them is the amplitude of the tsunami at the epicenter.The time of the maximum displacement to occur on the fault is not at the beginning of the fault slipping but retards 23 s.
文摘Japan＇s first open sea offshore wind farm, Kamisu offshore windfarm Phase l, was stricken by an earthquake of intensity 6 on the Japanese seismic scale and a five-meter-high tsunami during the Great East Japan Earthquake on March 11,2011. The wind farm resumed operation on March 14 after checks revealed no damage to the system, even though the wind farm was temporarily forced to stop due to the grid failure caused by the earthquake. Wind turbines require a precise seismic design especially in an earthquake-prone country such as Japan. Wind power Kamisu Phase 2 was built one year after the earthquake based on the experience of Kamisu Phase 1. This paper presents the seismic design of offshore wind turbines and the situation during the earthquake and tsunami.
文摘On February 8,2025,a remote area in the Caribbean Sea was rocked by a large M_(W)7.6(USGS,2025) earthquake,centered 209 km SSW of Georgetown,the capital of the Cayman Islands,and the largest city(population~41 000) of the British Overseas Territories(Figure 1).The earthquake was significant due to its large magnitude,potential regional impact,and the possibility of generating a tsunami.
