Rates of thrust faulting at the front of the Precordillera in western Argentina: Implications for the seismic hazard in Mendoza city from surface expose dating and paleoseismology

阿根廷西部 Precordillera 前部的逆冲断层速率：地表暴露测年和古地震学对门多萨市地震灾害的影响

基本信息

批准号：
46260672
负责人：
Professor Dr. Ralf Hetzel
金额：
--
依托单位：
Institut für Geologie und Paläontologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2007
资助国家：
德国
起止时间：
2006-12-31 至 2011-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/46260672?language=en
关键词：
Rates thrust faulting front Precordillera

项目摘要

A significant amount of the current plate convergence between the Nazca and the South American Plate is taken up in the back-arc region of the Andes. Between latitude 28°S and 33.5°S many large historical intraplate earthquakes document that ongoing deformation is concentrated along the front of the Precordillera and the basement uplifts of the Sierra Pampeanas farther east. Long-term slip rates of active thrust faults at the mountain front of the Precordillera are not known, although these faults pose a serious threat to major cities at the front of the Precordillera. At two surface-breaking thrusts near Mendoza city we will combine geomorphic mapping, topographic surveying, exposure dating of tectonically offset river terraces, paleoseismologic investigations, and luminescence dating in order to determine (1) the long-term rates of vertical uplift and horizontal shortening and (2) the frequency of destructive earthquakes on these faults in the past. Comparison of the longterm shortening rates with short-term velocities inferred from GPS data (~5 mm/a) will provide important insight into temporal variations in the rate of faulting, i.e. changes in the frequency of earthquakes. The planned investigations will help to better constrain crustal deformation at the front of the Precordillera and thus the seismic hazard for Mendoza city.

在安第斯山脉的后弧区域中，纳斯卡和南美板块之间的当前板块收敛大量。在28°S的纬度和33.5°之间，许多大型历史板岩内地震证明持续变形集中在Precordillera的前部和塞拉利昂pampeanas的地下升高的前部。尽管这些断层对Precordillera前部的主要城市构成了严重的威胁，但在Precordillera山区前部有主动推力断层的长期滑动速率并不是。在门多萨市附近的两个露面的推力下，我们将结合地貌映射，地形测量，构造构造的暴露约会，构造偏移河露台，古介质学研究和发光日期，以确定（1）垂直上升缩短和水平缩短的长期速率，以及（2）destructive of destructive of theme of thebe of therefs of thebe of there taffs of theme of thebes of thebe sonfors of thebe sonfors of这些缺陷。比较长期缩短率与从GPS数据（〜5 mm/a）推断出的短期速度的比较将为断层率的暂时变化，即地震频率的变化提供重要的见解。计划的调查将有助于更好地限制precordilera前部的地壳变形，从而更好地限制了门多萨市的地震危险。