The September 8–9, 1998 Rain-Triggered Flood Events at Motozintla, Chiapas, Mexico
The September 8–9, 1998 Rain-Triggered Flood Events at Motozintla, Chiapas, Mexico
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1998 年 9 月 8 日至 9 日，墨西哥恰帕斯州 Motozintla 因降雨引发洪水
DOI：
10.1007/s11069-005-4987-7
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发表时间：
2006
期刊：
影响因子：
3.7
通讯作者：
J. M. Sánchez
中科院分区：
文献类型：
--
作者：
L. Caballero;J. L. Macías;A. García;G. Saucedo;L. Borselli;D. Sarocchi;J. M. Sánchez
1998年9月，热带风暴“厄尔”席卷墨西哥南部，给瓦哈卡州和恰帕斯州带来强降雨。受灾最严重的城市是位于阿连德、拉米纳和谢拉茹格兰德河流域的莫托津特拉。9月8日和9日的降雨量分别为175毫米和130毫米，在两天内重复了该地区的月平均降雨量。莫托津特拉附近发生了多起山体滑坡，将大量物质倒入Xelajú Grande河。这些沉积物中的大部分随后被重新移动，产生泥石流，高浓缩流和充满沉积物的流，淹没了莫托津特拉市的大部分地区。水流覆盖面积约为3.15平方公里，最小沉积物体积为4.4 × 106立方米。莫托津特拉与恰帕斯州其他地区的交通中断了大约一个月，饮用水、食物、电力和燃料的供应也中断了。莫托津特拉周围的地质记录表明，在过去的6000年里，Xelajú Grande河一直是类似大洪水的通道。最古老的存款的放射性碳年龄为5320 ± 100 14 C年。在过去的100年里，至少发生了两次历史性的洪水，这一时期由1902年的地层不同的火山灰定义。对莫托津特拉地区日降雨量历史记录的频率分析表明，像1998年9月这样的事件的重复间隔约为25年。在1998年的灾难性洪水之后，市政当局采取的减灾措施没有考虑到地质和环境因素，也没有考虑到流量大小和适当的减灾技术，结果是莫托津特拉仍然面临未来洪水的严重风险。2005年10月初，莫托津特拉再次受到斯坦飓风引发的强降雨的严重破坏。
In September 1998 tropical storm “Earl” swept southern Mexico, producing intense rainfall in the states of Oaxaca and Chiapas. Among the most devastated cities was Motozintla, located in the drainage basin of the Allende, La Mina and Xelajú Grande Rivers. The rainfall from the tropical storm totaled 175 mm on September 8 and 130 mm on September 9, duplicating in two days the average monthly precipitation in the region. Numerous landslides occurred in the vicinity of Motozintla, depositing large volumes of material into the Xelajú Grande stream. Much of this sediment was subsequently remobilized, yielding debris flows, hyperconcentrated flows, and sediment-laden flows that inundated most sections of Motozintla city. The flows covered an approximate area of 3.15 km2 with a minimum volume of 4.4 × 106 m3 of sediment. Communication of Motozintla with the rest of the Chiapas State was interrupted for about a month, as was the supply of potable water, food, electricity, and fuel. The geologic record around Motozintla indicates that the Xelajú Grande River has been a pathway for similar large floods during the last 6000 years. The oldest deposit yielded a radiocarbon age of 5320 ± 100 14C years. B.P. At least two historic floods have occurred during the last 100 years, a time period defined by a stratigraphically distinct tephra of 1902. Frequency analysis of the historical record of daily rainfall in the Motozintla area suggests that events like that of September, 1998, have a recurrence interval of about 25 years. After the catastrophic flows of 1998, the mitigation measures by Municipal Authorities were made without regard to geological and environmental factors, or to taking into consideration the flow magnitude and appropriate hazard-mitigation techniques, with the result that Motozintla remains at serious risk for future floods. Unfortunately, prior to the publication of this study, in early October 2005, Motozintla was seriously damaged again by intense rain provoked by Hurricane Stan.