2019年10月31日南非夸祖鲁-纳塔尔地震的宏观地震分析和震源机制的确定

IF 1.2 4区 地球科学 Q2 GEOLOGY
B. Manzunzu, V. Midzi, T. Zulu, K. Mphahlele
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引用次数: 0

摘要

2019年10月31日格林尼治标准时间11:19,南非夸祖鲁-纳塔尔省Sunduza地区发生地震(震级,ML=3.8)。地震发生在Ntlakwe Bongwan断层的宽阔断裂带附近,南非东海岸有震感。通过采访公众和填写问卷进行宏观地震调查,评估事件的影响。对所有收集到的宏观地震数据的分析表明,震中附近和沿海地区出现了莫迪定义的麦卡利强度为IV-V和V的最大震动。在震中东北约100公里的德班部分地区也出现了类似的强度值。如此长距离的震动归因于场地效应引起的地面运动放大。使用第一次运动极性和振幅比获得的事件的断层平面解显示,沿185.0°走向的断层存在正断层,以68.0°倾斜,倾角为-52.0°。震源机制解的走向与Ntlakwe Bongwan断层带和附近断层的走向一致,表明该事件可能沿着该断层的一个断裂段破裂,该断裂段位于北部。所获得的倾角也与高角度断层一致,与沿Ntlakwe Bongwan断层观察到的断层相当。震中地区断层严重,但活动情况尚不清楚。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Macroseismic analysis and the determination of a focal mechanism of the 31 October 2019, KwaZulu-Natal earthquake in South Africa
An earthquake (magnitude, ML = 3.8) occurred on 31 October 2019 at 11:19 hours Greenwich Mean Time (GMT) in the Sunduza area of the KwaZulu-Natal (KZN) Province in South Africa. The earthquake was located near the broad fracture zone of the Ntlakwe-Bongwan fault and was felt along the eastern coast of South Africa. The effects of the event were assessed by conducting macroseismic investigations through interviewing members of the public and completing questionnaires. Analysis of all the collected macroseismic data showed that maximum shaking with Modified Mercalli Intensity of IV-V and V were experienced near the epicentral area as well as along the coast. Similar intensity values were also experienced in some parts of Durban about 100 km northeast of the epicentre. Shaking at such long distances was attributed to ground motion amplification due to site effects. A fault plane solution of the event obtained using both the first motion polarities and amplitude ratios showed normal faulting along a fault oriented in a strike of 185.0°, dipping at 68.0° with a rake of -52.0°. The strike of the focal mechanism solution aligns with the strike of the Ntlakwe-Bongwan fault zone and nearby faults suggesting that the event might have ruptured along one of the fracture segments of this fault mapped to the north. The obtained dip is also in line with a high angle fault comparable to that observed along the Ntlakwe-Bongwan fault. The epicentral region is highly faulted although the activity is not known.
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来源期刊
CiteScore
3.60
自引率
5.60%
发文量
18
审稿时长
>12 weeks
期刊介绍: The South African Journal of Geology publishes scientific papers, notes, stratigraphic descriptions and discussions in the broadly defined fields of geoscience that are related directly or indirectly to the geology of Africa. Contributions relevant to former supercontinental entities such as Gondwana and Rodinia are also welcome as are topical studies on any geoscience-related discipline. Review papers are welcome as long as they represent original, new syntheses. Special issues are also encouraged but terms for these must be negotiated with the Editors.
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