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ISSN 2096-7780 CN 10-1665/P

邓文泽. 2021年3月5日新西兰克马德克群岛M7.8面波震级测定差异分析 [J]. 地震科学进展, 2021, (9): 395-399. doi: 10.3969/j.issn.2096-7780.2021.09.002" target="_blank"> 10.3969/j.issn.2096-7780.2021.09.002" target="_blank" class="mainColor"> 10.3969/j.issn.2096-7780.2021.09.002" target="_blank"> 10.3969/j.issn.2096-7780.2021.09.002.
引用本文: 邓文泽. 2021年3月5日新西兰克马德克群岛M7.8面波震级测定差异分析 [J]. 地震科学进展, 2021, (9): 395-399. doi: 10.3969/j.issn.2096-7780.2021.09.002" target="_blank"> 10.3969/j.issn.2096-7780.2021.09.002" target="_blank" class="mainColor"> 10.3969/j.issn.2096-7780.2021.09.002" target="_blank"> 10.3969/j.issn.2096-7780.2021.09.002.
Deng Wenze. Difference in determination of surface wave magnitude of the M7.8 Kermadec Island earthquake on March 5,2021 in New Zealand [J]. Progress in Earthquake Sciences, 2021, (9): 395-399. doi: 10.3969/j.issn.2096-7780.2021.09.002" target="_blank"> 10.3969/j.issn.2096-7780.2021.09.002" target="_blank" class="mainColor"> 10.3969/j.issn.2096-7780.2021.09.002" target="_blank"> 10.3969/j.issn.2096-7780.2021.09.002.
Citation: Deng Wenze. Difference in determination of surface wave magnitude of the M7.8 Kermadec Island earthquake on March 5,2021 in New Zealand [J]. Progress in Earthquake Sciences, 2021, (9): 395-399. doi: 10.3969/j.issn.2096-7780.2021.09.002" target="_blank"> 10.3969/j.issn.2096-7780.2021.09.002" target="_blank" class="mainColor"> 10.3969/j.issn.2096-7780.2021.09.002" target="_blank"> 10.3969/j.issn.2096-7780.2021.09.002.

2021年3月5日新西兰克马德克群岛M7.8面波震级测定差异分析

Difference in determination of surface wave magnitude of the M7.8 Kermadec Island earthquake on March 5,2021 in New Zealand

  • 摘要: 2021年3月5日新西兰克马德克群岛发生M7.8地震,本文计算了全球台网692个台站和中国地震台网全球监测台网112个台站的面波震级,并对此震级进行了偏差分析。结果表明:由于面波震级测定公式的不同,我国和美国测震的面波震级偏差为0.2;面波震级的测定受震源破裂过程的影响,由于此次地震主要破裂方向沿北东向,地震的多普勒效应导致震中北东向的台站面波震级偏大,同时在震中北西向存在较小的滑动量,导致北西向的台站面波震级略低于北东向;而震中西南和东南方向的震动较弱,面波震级较小,地震速报受限于时效性,速报中测定面波的台站基本位于震中以南方向,故测定震级偏小。

     

    Abstract: A magnitude M7.8 earthquake struck Kermadec Island, New Zealand on March 5, 2021. In this study we determined surface wave magnitude using 692 stations from USGS global networks and 112 stations from China global earthquake monitoring system, then analyzed the difference. Results reveal that: China’s surface magnitude is always 0.2 larger than America’s due to different formula in calculating surface wave magnitude; Surface wave magnitude determination is effected by the rupture process of the mainshock. As the major slip occurred in the northeast direction, those stations with larger magnitude are mainly in the northeast direction of epicenter due to the seismic Doppler effect. Moreover, there is a small amount of slip in the northwest direction of the epicenter, resulting in the surface wave magnitude of the station in the northwest direction being slightly lower than that in the northeast direction; While weaker vibration is found in the south of the epicenter resulting smaller surface wave magnitude. The earthquake quickly determination by CENC was issued in 27 minutes after mainshock with relatively small surface magnitude since the station that measured the surface wave is basically located south of the epicenter.

     

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