Volcano-air-sea interactions in a coastal tuff ring, Jeju Island, Korea

The Holocene tuff ring of Songaksan, Jeju Island, Korea, is intercalated with wave-worked deposits at the base and in the middle parts of the tuff sequence, which are interpreted to have resulted from fair-weather wave action at the beginning of the eruption and storm wave action during a storm surge event in the middle of the eruption, respectively. The tuff ring is overlain by another marine volcaniclastic formation, suggesting erosion and reworking by marine processes because of post-eruption changes of the sea level. Dramatic changes of the chemistry, accidental componentry, and ash-accretion texture of the pyroclasts are also observed between the tuff beds deposited before and after the storm invasion. The ascent of a new magma batch, related to the chemical change, could not be linked with either the Earth and ocean tides or the meteorological event. However, the changes of the pyroclasts texture suggest a sudden change of the diatreme fill from water-undersaturated to supersaturated because of an increased supply of external water into the diatreme. Heavy rainfall associated with the storm is inferred to have changed the water saturation in the diatreme. Songaksan demonstrates that there was intimate interaction between the volcano and the environment.

ANALYSIS OF A SCHOOL BUILDING AGAINST TYPHOON HAIYAN STORM SURGE FORCES

In 2013 Typhoon Haiyan dealt strong winds and storm surges to Tacloban City, Philippines. After that, the standard public school buildings were designed using the load provisions of the updated 2015 National Structural Code of the Philippines. However, it is important to analyze if the school buildings can resist failure against another Haiyan storm surge event. Haiyan was simulated using the the Weather Research and Forecasting (WRF) Model, and the storm surge was simulated using the Finite Volume Community Ocean Model (FVCOM). The wind and flood loads were then calculated and applied on a two-story school building model in STAAD.Pro, and the maximum shear forces and bending moments in the 300 beams and columns were compared to its capacity.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/P3E1_aizbnE

SENSITIVITY OF TROPICAL CYCLONE TRACK TO ASSESSMENT OF SEVERE STORM SURGE EVENT AT TOKYO BAY

In total 82 tropical cyclones data was used to determine scenarios of translation speed, minimum central pressure and track for risk assessment of storm surge at Tokyo Bay. The numerical simulation of waves and flows was conducted by solving non-linear long wave equations. The maximum surge height shows that the typhoon passing through along northeast directional track is dangerous for Tokyo Bay. This trend confirms the previous risk assessment was reasonable. However, it has been shown that the typhoon passing through along north directional track is also dangerous although the frequency is low. Especially, it is interesting that the typhoon passing through along northwest directional track causes distinctive resurgence and harbor oscillation.

INTER-COMPARISON OF COASTAL MODELS: CASE STUDY OF STORM SURGE AT NEMURO IN JAPAN

The numerical coastal circulation models play an essential role in predicting storm surges. Several models (e.g. ADCIRC: Dietrich et al., 2004, FVCOM: Chen et al., 2003) have been previously inter-compared (Kerr et al., 2013; Chen et al., 2013). In these studies, storm surges were reproduced in locations where the bathymetry has a gradual increase from offshore to coast, within a closed gulf. On the other hand, there are few studies in regards to modelling storm surge where the near coast bathymetry is steep and connected to open ocean. Considering the storm surge dependence on local bathymetry, it can be important to conduct an inter-comparison of ocean circulation models in such a region. In this study, numerical coastal circulation models (2D-ADCIRC and 3D-FVCOM) are compared by using a 2014 Dec. storm surge event at Nemuro city in Hokkaido (Japan), which was caused by a rapidly intensified extra-tropical cyclone approaching the area. In this region, local bathymetry is steep due to Japan Trench. The cyclone caused a storm surge of nearly up to 1.8 m within the Nemuro city between 00:00 UTC 16th and 17th Dec. 2014. The aim of this study is to evaluate the performance of ocean circulation models using several air-sea drag coefficients and contribute to inter-comparison studies using ADCIRC and FVCOM.

Field survey of Typhoon Hato (2017) and a comparison with storm surge modeling in Macau

On 23 August 2017 a Category 3 hurricane, Typhoon Hato, struck southern China. Among the hardest hit cities, Macau experienced the worst flooding since 1925. In this paper, we present a high-resolution survey map recording inundation depths and distances at 278 sites in Macau. We show that one-half of the Macau Peninsula was inundated, with the extent largely confined by the hilly topography. The Inner Harbor area suffered the most, with a maximum inundation depth of 3.1 m at the coast. Using a combination of numerical models, we simulate and reproduce this typhoon and storm surge event. We further investigate the effects of tidal level and sea level rise on coastal inundations in Macau during the landfall of a “Hato-like” event.

Field survey of the 2017 Typhoon Hato and a comparison with storm surge modeling in Macau

On August 23, 2017 a Category 3 Typhoon Hato struck Southern China. Among the hardest hit cities, Macau experienced the worst flooding since 1925. In this paper, we present a high-resolution survey map recording inundation depths and distances at 278 sites in Macau. We show that one half of the Macau Peninsula was inundated with the extent largely confined by the hilly topography. The Inner Harbor area suffered the most with the maximum inundation depth of 3.1 m at the coast. Using a combination of numerical models, we simulate and reproduce this typhoon and storm surge event. We further investigate the effects of tidal level and sea level rise on coastal inundations in Macau during the landfall of a Hato like event.

Estimation of insurance-related losses resulting from coastal flooding in France

A model has been developed in order to estimate insurance-related losses caused by coastal flooding in France. The deterministic part of the model aims at identifying the potentially flood-impacted sectors and the subsequent insured losses a few days after the occurrence of a storm surge event on any part of the French coast. This deterministic component is a combination of three models: a hazard model, a vulnerability model, and a damage model. The first model uses the PREVIMER system to estimate the water level resulting from the simultaneous occurrence of a high tide and a surge caused by a meteorological event along the coast. A storage-cell flood model propagates these water levels over the land and thus determines the probable inundated areas. The vulnerability model, for its part, is derived from the insurance schedules and claims database, combining information such as risk type, class of business, and insured values. The outcome of the vulnerability and hazard models are then combined with the damage model to estimate the event damage and potential insured losses. This system shows satisfactory results in the estimation of the magnitude of the known losses related to the flood caused by the Xynthia storm. However, it also appears very sensitive to the water height estimated during the flood period, conditioned by the junction between seawater levels and coastal topography, the accuracy for which is still limited by the amount of information in the system.

Estimation of insurance related losses resulting from coastal flooding in France

A model has been developed in order to estimate insurance-related losses caused by coastal flooding in France. The deterministic part of the model aims at identifying the potentially flood-impacted sectors and the subsequent insured losses a few days after the occurrence of a storm surge event on any part of the French coast. This deterministic component is a combination of three models: a hazard model, a vulnerability model and a damage model. The first model uses the PREVIMER system to estimate the water level along the coast. A storage-cell flood model propagates these water levels over the land and thus determines the probable inundated areas. The vulnerability model, for its part, is derived from the insurance schedules and claims database; combining information such as risk type, class of business and insured values. The outcome of the vulnerability and hazard models are then combined with the damage model to estimate the event damage and potential insured losses. This system shows satisfactory results in the estimation of the magnitude of the known losses related to the flood caused by the Xynthia storm. However, it also appears very sensitive to the water height estimated during the flood period, conditioned by the junction between sea water levels and coastal topography for which the accuracy is still limited in the system.