Paleoseismology along the 1980 surface rupture of the Irpinia Fault: Implications for earthquake recurrence in the southern Apennines, Italy
Paleoseismology along the 1980 surface rupture of the Irpinia Fault: Implications for earthquake recurrence in the southern Apennines, Italy
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沿 1980 年伊尔皮尼亚断层表面破裂的古地震学：对意大利亚平宁山脉南部地震复发的影响
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
G. Valensise
中科院分区：
文献类型：
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作者：
D. Pantosti;D. P. Schwartz;G. Valensise
伊尔皮尼亚断层是1980年伊尔皮尼亚6.9级地震的震源，并在意大利产生了第一个明确的历史地表断层。1980年在皮亚诺迪Pecore，一个平坦的山间盆地约5公里的仪器震中以南的断层陡坎挖沟，提供了第一个数据地震复发间隔，每一个事件的滑动，并在亚平宁山脉南部断层带的一个主要的正断层的滑动率。这些海沟暴露了1980年前发生在过去8600年中的四次古地震的证据。尽管单个事件之间的时间间隔变化高达2倍，但平均复发间隔的最佳估计为2150年。每一次古地震在滑动量和变形方式上都与1980年的地表破裂相似，这表明1980年的地震是Irpinia断裂的特征。每次滑动值平均为61 cm。8600卡年以来的净垂直位移为2.12-2.36米，垂直滑动速率为0.25-0.35毫米/年，倾向滑动速率为0.29-0.40毫米/年，伸展速率为0.14-0.20毫米/年。虽然只有Irpinia断层的断层行为数据可用，但它们为评估亚平宁山脉南部的地震复发和变形率提供了一个起点。他们认为，（1）基于历史地震记录的断层特定地震复发间隔高估了大震级（M7）地震的发生率，（2）全新世亚平宁山脉的伸展速率≤1 mm/年。1980年的地震和古地震观测表明，在亚平宁山脉南部发生了重复和局部的地表断层活动，留下了微妙但独特的地貌证据，可以通过详细和仔细的调查来发现。
The Irpinia fault was the source of the Ms 6.9 1980 Irpinia earthquake and produced the first unequivocal historical surface faulting in Italy. Trenching of the 1980 fault scarp at Piano di Pecore, a flat intermontane basin about 5 km south of the 1980 instrumental epicenter, provides the first data on earthquake recurrence intervals, slip per event, and slip rate on a major normal fault in the Southern Apennines fault zone. The trenches exposed evidence of four pre-1980 paleoearthquakes that occurred during the past 8600 years. A best estimate average recurrence interval is 2150 years, although the time interval between individual events varies by as much as a factor of 2. Each paleo earthquake is similar to the 1980 surface rupture in amount of slip and style of deformation, which suggests that the 1980 event is characteristic for the Irpinia fault. Slip per event values average 61 cm. The net vertical displacement of 2.12–2.36 m since 8600 cal year B.P. observed in the trenches gives a vertical slip rate of 0.25–0.35 mm/yr, a dip slip rate of 0.29–0.40 mm/yr, and an extension rate of 0.14–0.20 mm/yr. Although fault behavior data are only available for the Irpinia fault they provide a starting point for evaluating earthquake recurrence and rates of deformation in southern Apennines. They suggest that (1) fault specific earthquake recurrence intervals based on the historical seismic record overestimates the occurrence of large magnitude (M7) earthquakes and (2) the Holocene rate of extension across the Apennines is ≤1 mm/yr. The 1980 earthquake and the paleoseismologic observations show that repeated and localized surface faulting occurs in southern Apennines and leaves subtle but distinct geomorphic evidence that can be detected with detailed and careful investigation.