The Shoreline Deformation in Convex Beach due to Sea Level Rise

Sea level rise (SLR) is become more serious on a global scale and has become one of the main reasons causes shoreline changes, and erosion, even on an extreme scale can cause the sinking of coastal areas and islands. It was recorded that many big cities were damaged by SLR. The Bruun rule is the most widely used method for predicting the horizontal translation of the shoreline associated with a given rise in sea level. In this study, however, the change in the average shoreline at the convex beach, which is more vulnerable to erosion due to sea level rise, is investigated. The increase in water depth by sea level rise causes a change in the wave crestline, ultimately leading to a linearization of the shoreline. In general, it is assumed that the annual average shoreline is parallel to the annual mean wave crestline. Moreover, assuming that the equilibrium depth contour is formed according to the crestline, the retreat of the shoreline is predicted. The shoreline change is indirectly predicted through the wave crestline deformation obtained from a wave model and this method is applied to the convex beach. Our result showed that for a convex beach with a length of 1 km has open ends with free littoral drift at both ends, the sea level rise of 1 m cause the erosion of 10 m in the protruding area, and the sea level rise of 2 m causes erosion of 23 m. However, if the convex beach is blocked at both ends, sea level rise of 1 m causes the erosion of 6.3 m in the convex area, but the shoreline advance of 3.8 m at both ends, and if the sea level rise of 2 m occurs, the erosion of 14.3 m can occur in the convex area and shoreline advance of 8.6 m can occur at both ends.

Depth Contours and Coastline Generalization for Harbour and Approach Nautical Charts

Generalization of nautical charts and electronic nautical charts (ENCs) is a critical process which aims at the safety of navigation and clear cartographic presentation. This paper elaborates on the problem of depth contours and coastline generalization—natural and artificial—for medium-scale charts (harbour and approach) taking into account International Hydrographic Organization (IHO) standards, hydrographic offices’ (HOs) best practices and cartographic literature. Additional factors considered are scale, depth, and seafloor characteristics. The proposed method for depth contour generalization utilizes contours created from high-resolution digital elevation models (DEMs) or those already portrayed on nautical charts. Moreover, it ensures consistency with generalized soundings. Regarding natural coastline generalization, the focus was on managing the resolution, while maintaining the shape, and on the islands. For the provision of a suitable generalization solution for the artificial shoreline, it was preprocessed in order to automatically recognize the shape of each structure as perceived by humans (e.g., a pier that looks like a T). The proposed generalization methodology is implemented with custom-developed routines utilizing standard geo-processing functions available in a geographic information system (GIS) environment and thus can be adopted by hydrographic agencies to support their ENC and nautical chart production. The methodology has been tested in the New York Lower Bay area in the U.S.A. Results have successfully delineated depth contours and coastline at scales 1:10 K, 1:20 K, 1:40 K and 1:80 K.

Analysis of subsurface structural trend and stratigraphic architecture using 2D seismic data: a case study from Bannu Basin, Pakistan

The present study is focused on the subsurface geology of Bannu Basin, a part of western Indus foreland Pakistan. For this purpose, some regional seismic profiles and deep exploratory wells data have been used in integration.A total of ten mappabale seismic reflection events have been identifed which are representative of specific geological units. In general, based on the seismic the formation trends, the horizons are dipping in the northwest direction of the study area. The area generally deepens toward the northwest due to sediments load toward the northwest. The seismic profile MWI-83 shows a unique faults bounded anticlinal structure that has also been mapped on the two-dimmensional contour maps. This could be regarded as potential hydrocarbon entrapment. The regional seismic profiles are contoured for the entire grid in both time and depth domain to obtain the clearer image of the subsurface individual stratigraphic units. The 2D contour maps for Lower Permian aged Warcha Sandstone, Middle Triassic aged Tredian Formation and Early Jurrasic aged Datta Formation have been prepared using gridded TWT of the seismic profiles. The time and depth contour maps of the Datta Formation and Tredian Formation show a four way clouser oriented in the southeast dierction. The area of the closure was computed which is 24 Sq km approximately. Furthermore, the formation tops of the five wells have been used to correlate the wells for understanding the lateral and vertical variations in the stratigraphic layers. The correlation shows that the Datta Formation’s thickness increases at the centre of the basin whereas decreases on the east and south flanks of the basin. Reasons of Wells failure were concluded on the basis of the final well report and concluded that these well failure occur due to poor quality of the data and also due to some mechanical problems. Reservoircharacterization using statistical rock physics and petrophysics coupled with core data analysis can provide further insights into the hydrocarbon exploration.

Pengolahan Data Multibeam untuk Membuat Lembar Lukis Teliti Guna Mengupdate Peta Laut Indonesia No. 376 (Studi Kasus Selat Ombai)

Penulisan ini didasari oleh peran Pushidrosal sebagai organisasi yang bertugas menyelenggarakan pembinaan Hidro-Oseanografi, untuk menjamin keselamatan navigasi pelayaran diseluruh wilayah perairan Indonesia. Penelitian ini bertujuan untuk 1) Mengolah data multibeam dengan format (.csar) guna mendapatkan data generated depth contour, depth area, dan sounding selection menggunakan perangkat lunak CARIS Bathy DataBASE 4.2 kemudian dijadikan Lembar Lukis Teliti (LLT); 2) Membandingkan Lembar Lukis Teliti (LLT) produk Dishidro Pushidrosal dengan Lembar Lukis Teliti (LLT) hasil penelitian yang menggunakan generated depth contour, depth area dan sounding selection; 3) Mengupdate Peta Laut Indonesia No. 376 menggunakan Lembar Lukis Teliti (LLT). Metode yang digunakan dalam penelitian ini adalah menggunakan data sekunder, yaitu data penelitian yang didapatkan melalui media perantara atau tidak secara langsung. Hasil yang didapatkan adalah perangkat lunak Bathy DataBASE 4.2 dapat memfasilitasi dalam penggambaran peta, khususnya pada Bathymetry content yang berupa Contour dan Sounding Selection sehingga memudahkan kartografer dalam melaksanakan generalisasi kontur.

TÍNH PHÂN BẬC CỦA ĐỊA HÌNH ĐÁY BIỂN QUANH MỘT SỐ ĐẢO VEN BỜ VIỆT NAM

Flattened seabed characters at the nearshore islands, namely Bach Long Vi, Con Co, Ly Son, Phu Quy, Hon Khoai and Tho Chu, were analysed based on depth contour map with 1 m vertical resolution and the application of ArcMap 10.4 software. Consequently, a series of seabed cross sections was automatically created by using the software, which provides the time-saving benefit and improves the scientific relevance. The result shows that flattened seabed characters of those islands were comparable in terms of general pattern, but still remained some distinctions depending on particular location. The depth of flattened seabed levels does not reach 30–50 m depth at northern and southern Vietnam’s sea (seabed surrounding Bach Long Vi, Hon Khoai, Tho Chu islands), while the value reaches over 100 m depth at southern central Vietnam’s sea (seabed surrounding Ly Son, Phu Quy islands). The classification of flattened seabed reveals the following depth levels: 0–2 m, 5–8 m, 12–14 m, 20–25 m, 25–27 m, 27–30 m, 32–35 m, 40–45 m, 45–50 m, 53–55 m, 60–65 m, 65–70 m, 75–85 m and 90–115 m.