Animated infographic as information media for earthquake and tsunami mitigation plan on the south coast of Bantul Indonesia

Bantul is a district located in the southern part of Yogyakarta Indonesia. Its located in the lowlands with coastal area on its border, Bantul is a district with the longest coastline in Yogyakarta Province, about 15.65 km. This condition makes Bantul Regency prone to earthquakes and tsunamis from the south coast. In normal situations, disaster management training and simulations are often carried out. However, during the current pandemic, this is no longer possible. This study aims to design an informative and effective information media about tsunami mitigation plan for the community in the pandemic situation. The research applied was descriptive qualitative method. The data were collected through literature study as the basis for designing infographic media. The result of this research is an animated infographic that uses a flat design visual style and is delivered in Javanese language.

A Note on The Design of Seawall for Tsunami Disaster Mitigation

Many coastal structures or structures in coastal areas were destroyed by a tsunami attack. Such destructions were due primarily to the fact that such structures were not designed to withstand a tsunami. Those which were designed to withstand tsunami force may also have been destroyed due to some damaging factors which were not included in the design. The damage of the coastal structures is one of the important factors that have caused casualties. Especially, when the destroyed structures were originally aimed to mitigate the area against tsunami, they may cause higher fatalities. Examples of such structures are sea walls in many parts of Japan which were destroyed by the 2011 tsunami. This paper discusses the important factors relevant to the damage of seawall as tsunami mitigation structure such as impact force due to tsunami front, hydrostatic force, and hydrodynamic force, debris force and scour due tsunami. The study was carried out based on literature about the damages of seawall as tsunami protection structures and laboratory experiment reports. The destructions to the structures were divided into three classifications namely instantaneous direct destruction due to impact and drag forces, slowly direct destruction due to drag force, and slowly indirect destruction due to scour. Finally, important aspects to be considered in the design of seawall as tsunamis protection were proposed.

Probabilistic Tsunami Hazard Analysis of Inundated Buildings Following a Subaqueous Volcanic Explosion Based on the 1716 Tsunami Scenario in Taal Lake, Philippines

A probabilistic hazard analysis of a tsunami generated by a subaqueous volcanic explosion was performed for Taal Lake in the Philippines. The Taal volcano at Taal Lake is an active volcano on Luzon Island in the Philippines, and its eruption would potentially generate tsunamis in the lake. This study aimed to analyze a probabilistic tsunami hazard of inundated buildings for tsunami mitigation in future scenarios. To determine the probabilistic tsunami hazard, different explosion diameters were used to generate tsunamis of different magnitudes in the TUNAMI-N2 model. The initial water level in the tsunami model was estimated based on the explosion energy. The tsunami-induced inundation from the TUNAMI-N2 model was overlaid on the distribution of buildings. The tsunami hazard analysis of inundated buildings was performed by using the maximum inundation depth in each explosion case. These products were used to calculate the probability of the inundated building given the occurrence of a subaqueous explosion. The results from this study can be used for future tsunami mitigation if a tsunami is generated by a subaqueous volcanic explosion.

Flume Experiments on Flow Analysis and Energy Reduction through a Compound Tsunami Mitigation System with a Seaward Embankment and Landward Vegetation over a Mound

As a countermeasure against tsunami inundation, the present study conducted a series of laboratory experiments using a compound mitigation system in which a seaward embankment (E) followed by landward coastal vegetation (V) over a mound (M) (EMV) was investigated in supercritical flow conditions. The changes of flow around the mitigation system and energy reduction were clarified under varying conditions of mound height and vegetation density. Cases of an embankment followed by only a mound (EMNV) were also considered for comparison. Experimental results showed that three basic types of flow structures were observed within the mitigation system in EMV cases. A water cushion was created within the mitigation system mainly due to the combined effects of the mound and vegetation. It significantly reduced the maximum total energy in EMV cases by approximately 41–66%, whereas in EMNV cases, the maximum energy reduction was found to be 23–65%. Increments in both mound height and vegetation density increased the intensity of the water cushion within the mitigation system by offering more drag and reflecting the flow, and hence, significantly reduced the energy of the flow.

STUDY OF TSUNAMI MITIGATION BASED ON VEGETATION IN SERENTING BEACH, MANDALIKA SPECIAL ECONOMIC ZONE, LOMBOK ISLAND

Serenting Beach is one of the beaches in the Mandalika Special Economic Zone (MSEZ), Central Lombok Regency. The MSEZ is located in the southern part of Lombok Island and faces the Indian Ocean. The Mandalika Special Economic Zone is prospected to expedite the sector of tourism at Province of West Nusa Tenggara which is very potential. A few hundred kilometers to the south part of Lombok Island is one of the large tectonic plates meeting zones which is a major source of potential tsunami earthquakes. With the geological conditions of Lombok Island which is prone to tsunamis and the existence of environmental degradation in Serenting Beach, MSEZ, it is necessary to conduct research about study of tsunami mitigation based on vegetation in Serenting Beach, MSEZ, Lombok Island. Based on the research, there are several types of plants that need to be planted as a tsunami disaster mitigation effort in Serenting Beach, MSEZ, namely: Casuarina equisetifolia, Pandanus odoratissimus, Cocos nucifera, Hibiscus tiliaceus, and Terminalia catappa. The government and various related parties need to provide education to the public, tourism managers, and tourists to take an active role in protecting vegetation and not through illegal logging.

Perencanaan Lanskap Mitigasi Tsunami Berbasis Ekosistem Mangrove di Kota Palu

The coastal areas are vulnerable areas to disaster threats, especially the geological hazards of earthquakes accompanied by tsunamis. Palu City, which is located on the west coast of Sulawesi, experienced a natural disaster of an earthquake, tsunami, and liquefaction on September 28, 2018. Based on the Map of Disaster Prone Index in Central Sulawesi Province, Palu City is a tsunami-prone area that is crossed by the Palu-Koro Fault. Tsunami disaster mitigation efforts in coastal areas can be done by planting mangrove ecosystems as a green barrier. The purpose of this study is to analyze the characteristics of the coastal landscape in Palu City and plan the landscape of tsunami mitigation based on mangrove ecosystems in Palu City. The method used spatial analysis method and descriptive method, as well as the research stage, consists of preparation, data analysis, data synthesis, and landscape planning stage. The basic concept of tsunami mitigation landscape planning is to reduce or eliminate disaster risk in coastal areas based on mangrove ecosystems. The concept of spatial pattern concept consists of high hazard zones, medium hazard zones, and low hazard zones. The concept of vegetation refers to the diversity of mangrove and native plant species as green open spaces and green barriers.