Near-trench slip potential of megaquakes evaluated from fault properties and conditions. Real-Time GNSS Analysis System REGARD: An Overview and Recent Results. The spread of the source area of the 1944 Tonankai earthquake was rather short and stopped before the Tokai earthquake fault segment. Web. [39] Figure 12 shows changes of the water height in Ryujin Lake and the flow speed of water in the entrance of the lake connecting to the channel. [25] We first set a 70 km by 120 km subfault segment, N5, on the west of the N4 subfault segment and extended the source rupture area of the Hoei earthquake to Hyuga‐nada (Figure 7). Application of Vector-Type Super Computer to Understanding Giant Earthquakes and Aftershocks on Subduction Plate Boundaries. A simulation of the tsunami runup into Ryujin Lake using the onshore tsunami estimated by the new model demonstrates a tsunami inundation process; inflow and outflow speeds affect transport and deposition of sand in the lake and around the channel connecting it to the sea. Le bilan total s'élève à plus de 29 000 bâtiments détruits et plus de 5 000 victimes. Nankai earthquake (南海地震) measuring 8.4 hit at 4:19 [local time] there was a catastrophic earthquake on the southwest of Japan in the Nankai area. Nankaido, Japan Estimated Number of Deaths: 31,000 Year: 1498. The tsunami inundated Ryujin Lake, acting together with subsidence of the coastline associated with the earthquake is also explained by the new source model very effectively. [19] Tsunami lakes on the shoreline of the Pacific coast along the Nankai Trough are aligned linearly over the area where large ground subsidence has occurred during Nankai Trough earthquakes (Figure 2). La dernière modification de cette page a été faite le 17 octobre 2019 à 16:22. Source models of historical events such as the Hoei earthquake, on the other hand, have mostly been deduced from descriptions of earthquake phenomenon in ancient documents such as shaking felt by humans, damage to houses, and visual measurements of tsunami inundation or tsunami runup height. Thus, tsunami runup into Ryujin Lake might occur when the Nankai Trough fault rupture extends to Hyuga‐nada, but not during events like the 1854 Ansei Nankai and 1946 Showa Nankai earthquakes, in which the fault rupture did not extend past the westernmost end of Shikoku. Maximum tsunami height along the Pacific coast of Japan. Nankaido, Japan A magnitude 8.4 earthquake caused sea waves as high as 25 m to go into the Pacific coasts of Kyushyu, Shikoku and Honshin. In order to improve tsunami height and ground subsidence in Kyushu, we have to modify source model more drastically. The source rupture is assumed to start in the Kumano Sea off the Kii Peninsula, spreading bilaterally toward Kyushu and Suruga Bay at a rupture speed of Vr = 2.7 km/s. The tsunami runup into Ryujin Lake estimated by the tsunami inundation simulation using a high‐resolution bathymetry model demonstrates the process whereby a large flow of seawater with a large difference in inflow and outflow speeds can transport and deposit sea sand into the lake near the inflow channel very effectively. Japan has had two earthquakes with staggering death tolls of more than 100,000 people. Redeposition of volcaniclastic sediments by a tsunami 4600 years ago at Kushima City, south‐eastern Kyushu, Japan. Journal of Geomagnetism and Aeronomy, Nonlinear Tsunamis therefore occur comparatively often in this country. [2003] modified the source model of Aida [1981] and improved the agreement between tsunami simulations and observed tsunami height distributions. Apr 24, 1771. [20] We therefore examined other findings supporting our hypothesis of an extended source of the Hoei earthquake. Notes. We should be prepared for a diversity of rupture processes during future earthquakes along the Nankai Trough. The Nankai Trough earthquake tsunamis in Korea: numerical studies of the 1707 Hoei earthquake and physics-based scenarios. Re-examination of possible great interplate earthquake scenarios in the Nankai Trough, southwest Japan, based on recent findings and numerical simulations. Therefore, the large tsunami generated by the rupture of the N5′ subfault segment and the swift current it produces in the channel is the only agent that can explain the transport of sea sand into the lake. Nankaido Japan 28 October 1707 A magnitude 84 earthquake caused tsunamis as. Figure 9 shows the maximum simulated tsunami heights for the new model along the Pacific coast of Japan in Shikoku and Kyushu. Other source parameters, including strike, dip, rake and slip were assumed to be the same as for the N4 subfault segment (Table 2). EFFECT OF TSUNAMI-INDUCED SEDIMENT TRANSPORT AND OFFSHORE TSUNAMI WAVEFORM ON ENLARGEMENT OF RETURN FLOW. Le bassin de la préfecture de Nara présente des traces de liquéfaction des sols due au séisme[12]. Finally, this study suggests that earthquake rupture extent along the Nankai Trough may not be as limited as previously described: as combinations of subfaults to produce Nankai, Tonankai, or Tokai earthquakes, or as a grand combination of subfaults N1–N4 to produce a larger earthquake. The source rupture area of the new Hoei earthquake source model extends further, to the Hyuga‐nada, more than 70 km beyond the currently accepted location at the westernmost end of Shikoku. Imaging Shear Strength Along Subduction Faults. However, the height of the simulated tsunami from western Shikoku to Hyuga‐nada in Kyushu is less than half of the actual height observed. The Hoei earthquake was a larger event in which rupture spread as far as Hyuga‐nada, incorporating the fifth subfault, N5. The 2011 Tohoku-oki tsunami — Three years on. A possible explanation is that slow rupture over the N4 subfault segment generated large coseismic ground deformation and therefore a large tsunami, but did not produce strong ground motion. En plus des deux séismes de 1854, deux autres similaires se sont déclenchés en 1944 et en 1946. The 1498 Nankai earthquake occurred off the coast of Nankaidō, Japan, at about 08:00 local time on 20 September 1498. "How Tsunamis Work - Alex Gendler." It was 300 years ago, but it was one of the tragedies caused by the tsunami in Japan. [37] The results of the tsunami inundation simulation for the new Hoei earthquake model are shown in Animation S3 and in Figure 11 as a sequence of snapshots of the water surface of the Ryujin Lake after T = 14, 19, 24, 29, 34, and 39 min from the start of the earthquake, illustrating the way in which a tsunami with a large flux can inundate Ryujin Lake. If you do not receive an email within 10 minutes, your email address may not be registered, Tokaido-Nankaido, Japan Tsunami – A earthquake of 8.4 magnitude which caused 25 meter waves to engulf the coastal regions of Kyushyu, Shikoku, Honshin and Osaka in 1707. Ryujin Lake, however, recently observed by Okamura et al. Postseismic deformations of the ground surface during interearthquake cycles gradually resolve such earthquake‐induced deformation to a normal level over tens of years. Thus, further supporting evidence is needed to develop a reliable and detailed source rupture history for the Hoei earthquake. Geological and historical evidence of irregular recurrent earthquakes in Japan. 48C, Séisme de 2011 de la côte Pacifique du Tōhoku, Portail de la géodésie et de la géophysique, https://fr.wikipedia.org/w/index.php?title=Séisme_du_28_octobre_1707_de_l%27ère_Hōei&oldid=163614676, Page avec coordonnées similaires sur Wikidata, Portail:Géodésie et géophysique/Articles liés, Portail:Sciences de la Terre et de l'Univers/Articles liés, licence Creative Commons attribution, partage dans les mêmes conditions, comment citer les auteurs et mentionner la licence. However, these effects on amplifying tsunami subsides ground surface at Ryujin Lake in Kyushu would be very minor due to larger distances, and most tsunami developed by the splay fault propagates toward rectangular direction of the Trough axis but not to Kyushu. An Account of the Destructive Earthquakes in Japan, Publ. Fuji. Our new source model with the source rupture area extended to the Hyuga‐nada explains the large tsunami observed in Kyushu more consistently than previous models. Mega-earthquakes rupture flat megathrusts. La côte méridionale de l'île d'Honshu est située le long du chevauchement de Nankai, qui marque la subduction de la plaque des Philippines sous la plaque eurasienne. [4] In the recorded history of the Nankai Trough earthquakes the 1707 Hoei earthquake (hereafter called the Hoei earthquake) was the largest shock in modern Japanese history. The resultant large Shields number, (s > 11), associated with the tsunami's inflow 25 min from the start of the earthquake (Figure 11c), promises that tsunami could efficiently transport sea sand into the lake with very large Shields number of tsunami due to the rupture on the N5′ subfault [see, e.g., Takahashi et al., 1993]. [8] Recent developments of the Japanese GEONET nation‐wide GPS network illustrating the pattern of present ground deformation which is considered to be undergoing recovery process of post‐Nankai Trough earthquake. The rupture of each subfault takes 5 s. For simplicity, we assumed that the shape of the initial tsunami on the sea surface is identical to the sea bottom deformation associated with the earthquake. Thus, a Tokai earthquake has not occurred for more than 150 years since the 1854 Ansei Tokai earthquake. Thus, the area of the N5′ subfault is now a seismic gap since the Hoei earthquake in 1707. Small Bodies, Solar Systems Propagation of tsunami associated with the 1707 Hoei earthquake derived by tsunami simulation using the source model of. NUMERICAL EXPERIMENTS FOR IMPACTS OF TIDES ON TSUNAMI PROPAGATIONS IN THE SETO INLAND SEA. The earthquake, estimated at magnitude 8.4, was followed by a huge tsunami, but no estimates exist for the number of deaths. The Journal of the Geological Society of Japan. Our belief based on detail tsunami simulation is that the source rupture area of the Hoei earthquake extended an additional 70 km eastward to the Hyuga‐nada from the westernmost end of Shikoku. YouTube, n.d. Tokaido-Nankaido japan The tsunami was a magnitude of 8.4, with a total of 30,000 deaths. For example, historical archives document that at Yonouzu village, at the northern end of Hyuga‐nada, the tsunami was more than 10 m and killed 18 people [Chida et al., 2003; Chida and Nakayama, 2006]. Oct 28, 1707. We used a nested mesh model that connects gradually 30 m, 90 m, and 270 m mesh model to allow efficient simulation of the tsunami in heterogeneous bathymetry (Figure 3). The tsunami inundation simulation was conducted using a fine nested mesh model that connects gradually different mesh resolution of 30 m, 10 m, and 3.3 m. [36] Results from a former large‐mesh tsunami simulation, in which height and flux of the tsunami in two horizontal directions at the coast near Ryujin Lake were calculated using the larger (30 m) mesh, were used as inputs in the present tsunami inundation simulation. It agrees well with our expectation of gentle (40 cm) ground subsidence in the area around Ryujin Lake and some subsidence of the ground surface at Cape Ashizuri as noted by Kawasumi [1950]. However, it should be kept in mind that objective data, such as shaking intensities and tsunami heights in Kyushu, were rather limited at that time and thus, these data may not well incorporated in their analysis. 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