Abstract The contribution of tropical storms to a carbonate gravel bar formation is presented for Lumaniag village, northwestern Philippines, based on field measurements, high-precision U-Th dating of Porites sp. coral boulders (longest axis > 1 m), historical records of tsunamigenic earthquakes and typhoons, and anecdotal accounts. Results of U-Th dating suggest that the events which transported the sampled fully exposed boulders found on the gravel bar occurred during the 1960s to early 1970s; the underlying rubble are presumed to have been deposited by older inundation events. The U-Th ages are consistent with anecdotal accounts and records of typhoon tracks and damage reports from typhoons Dading (international name Winnie; 1964), Welming (international name: Emma; 1967), and several other strong typhoons in early 1970s. Hydrodynamic calculations estimate a minimum flow velocity of 3.2 m/s to initiate translocation of the largest coral boulders in the area. Potential shift in storm frequency and intensity over the next few decades suggests that the gravel bar will further accumulate carbonate sediments. With the mangroves contributing to its stability, the storm-deposited island-like feature contributes to the dissipation of approaching storm waves and provides natural protection for the nearby coastal community. The ridge will likely provide an effective buffer for extreme waves in the term unless destroyed by anthropogenic activities or an oversized extreme event.

中文翻译：

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菲律宾西北部八打雁 Lumaniag 村风暴造成的珊瑚巨石运输和砾石坝形成

摘要 基于野外测量和 Porites sp. 的高精度 U-Th 测年，介绍了热带风暴对菲律宾西北部 Lumaniag 村碳酸盐砾石坝形成的贡献。珊瑚巨石（最长轴 > 1 m）、海啸地震和台风的历史记录以及轶事。U-Th测年结果表明，在1960年代至1970年代初，运输在砾石坝上发现的采样的完全暴露的巨石的事件发生了；推测下面的瓦砾是由较早的洪水事件沉积的。U-Th年龄与台风大定（国际名称Winnie；1964）、维尔明（国际名称：Emma；1967）和1970年代初期其他几个强台风的台风轨迹和破坏报告的轶事记载和记录一致。流体动力学计算估计最低流速为 3.2 m/s，以启动该地区最大珊瑚巨石的易位。未来几十年风暴频率和强度的潜在变化表明砾石坝将进一步积累碳酸盐沉积物。红树林有助于其稳定，风暴沉积的岛状特征有助于消散接近的风暴浪，并为附近的沿海社区提供自然保护。除非被人为活动或过大的极端事件破坏，否则该山脊可能会在此期间为极端波浪提供有效的缓冲。未来几十年风暴频率和强度的潜在变化表明砾石坝将进一步积累碳酸盐沉积物。红树林有助于其稳定，风暴沉积的岛屿状特征有助于消散接近的风暴浪，并为附近的沿海社区提供自然保护。除非被人为活动或过大的极端事件破坏，否则该山脊可能会在此期间为极端波浪提供有效的缓冲。未来几十年风暴频率和强度的潜在变化表明砾石坝将进一步积累碳酸盐沉积物。红树林有助于其稳定，风暴沉积的岛状特征有助于消散接近的风暴浪，并为附近的沿海社区提供自然保护。除非被人为活动或过大的极端事件破坏，否则该山脊可能会在此期间为极端波浪提供有效的缓冲。