The September 16, 2015 Mw 8.3 Illapel, Chile Earthquake: characteristics of tsunami wave from near-field to far-field
-
摘要: 2015年9月16日,智利海岸发生Mw 8.3级地震,地震引发了局地海啸,在Coquimbo站监测到了4.4 m的海啸波。本文分别针对USGS的单一板块震源和NOAA海啸源数据库反演得到的多板块震源,基于实测数据分析和数值模拟相结合的方法分析海啸波从近场到远场的特征规律。本文选取了16个深水浮标,10个近岸潮位站,以及10个远场潮位站。采用基于非线性浅水方程的数值模型模拟得到的海啸波面时间序列与实测结果在深水浮标处较为吻合。由于近岸地形复杂、地形精度的精细度不够,在近岸潮位站的模拟结果与监测数据存在偏差。在近场的沿岸,海啸的最大波幅从0.1 m到2 m分布(Coquimbo站除外)。通过分析海啸波在深水中的传播过程,发现最大波幅从9.8 cm衰减为0.8 cm,表明在太平洋范围的深水传播过程是厘米尺度的海啸,频谱分析显示海啸波的周期为13~17 min和32 min。在距离震中超过一万公里的近岸,由于海啸的爬高过程和陆地边界反射引起的共振,使得海啸波的最大波幅增大到0.2 m~0.8 m。尽管此次地震海啸事件的影响较小,在当地仍然引起了不可忽视的海啸灾害以及整个太平洋范围内的海水波动。Abstract: On September 16, 2015, an earthquake with magnitude of Mw 8.3 occurred 46 km offshore from Illapel, Chile, generating a 4.4-m local tsunami measured at Coquimbo. In this study, the characteristics of tsunami are presented by a combination of analysis of observations and numerical simulation based on sources of USGS and NOAA. The records of 16 DART buoys in deep water, ten tidal gauges along coasts of near-field, and ten coastal gauges in the far-field are studied by applying Fourier analyses. The numerical simulation based on nonlinear shallow water equations and nested grids is carried out to provide overall tsunami propagation scenarios, and the results match well with the observations in deep water and but not well in coasts closed to the epicenter. Due to the short distance to the epicenter and the shelf resonance of southern Peru and Chile, the maximum amplitude ranged from 0.1 m to 2 m, except for Coquimbo. In deep water, the maximum amplitude of buoys decayed from 9.8 cm to 0.8 cm, suggesting a centimeter-scale Pacific-wide tsunami, while the governing period was 13-17 min and 32 min. Whereas in the far-field coastal region, the tsunami wave amplified to be around 0.2 m to 0.8 m, mostly as a result of run-up effect and resonance from coast reflection. Although the tsunami was relatively moderate in deep water, it still produced non-negligible tsunami hazards in local region and the coasts of far-field.
-
Key words:
- 2015 Illapel earthquake /
- tsunami observation /
- numerical modeling /
- far-field /
- near-field
-
An Chao, Sepúlveda I, Liu P L F. 2014. Tsunami source and its validation of the 2014 Iquique, Chile, earthquake. Geophysical Research Letters, 41(11):3988-3994 Aránguiz R, González G, González J, et al. 2016. The 16 September 2015 Chile Tsunami from the post-tsunami survey and numerical modeling perspectives. Pure and Applied Geophysics, 173(2):333-348 Arcos M E M, LeVeque R J. 2015. Validating velocities in the GeoClaw tsunami model using observations near Hawaii from the 2011 Tohoku tsunami. Pure and Applied Geophysics, 172(3-4):849-867 Catalán P A, Aránguiz R, González G, et al. 2015. The 1 April, 2014 Pisagua tsunami:observations and modeling. Geophysical Research Letters, 42(8):2918-2925 Contreras-López M, Winckler P, Sepúlveda I, et al. 2016. Field survey of the 2015 Chile Tsunami with emphasis on coastal wetland and conservation areas. Pure and Applied Geophysics, 173(2):349-367 DeMets C, Gordon R G, Argus D F. 2010. Geologically current plate motions. Geophysical Journal International, 181(1):1-80 Heidarzadeh M, Satake K. 2013. Waveform and spectral analyses of the 2011 Japan tsunami records on tide gauge and DART stations across the Pacific Ocean. Pure and Applied Geophysics, 170(6-8):1275-1293 Heidarzadeh M, Murotani S, Satake K, et al. 2016. Source model of the 16 September 2015 Illapel, Chile, Mw 8.4 earthquake based on teleseismic and tsunami data. Geophysical Research Letters, 43(2):643-650 Heidarzadeh M, Satake K, Murotani S, et al. 2015. Deep-water characteristics of the trans-Pacific tsunami from the 1 April 2014 Mw 8.2 Iquique, Chile Earthquake. Pure and Applied Geophysics, 172(3-4):719-730 Kendrick E, Bevis M, Smalley Jr R, et al. 2001. An integrated crustal velocity field for the central Andes. Geochemistry, Geophysics, Geosystems, 2(11):doi: 10.1029/2001GC000191 LeVeque R J, George D L, Berger M J. 2011. Tsunami modelling with adaptively refined finite volume methods. Acta Numerica, 20:211-289 Okada Y. 1985. Surface deformation due to shear and tensile faults in a half-space. Bulletin of the Seismological Society of America, 75(4):1135-1154 Okal E A. 2011. Tsunamigenic earthquakes:past and present milestones. Pure and Applied Geophysics, 168(6-7):969-995 Rabinovich A B, Candella R N, Thomson R E. 2013. The open ocean energy decay of three recent trans-Pacific tsunamis. Geophysical Research Letters, 40(12):3157-3162 Ren Zhiyuan, Liu Hua, Wang Benlong, et al. 2014. An investigation on multi-buoy inversion method for tsunami warning system in South China Sea. Journal of Earthquake and Tsunami, 8(3):1440004 Ren Zhiyuan, Wang Benlong, Fan Tingting, et al. 2013. Numerical analysis of impacts of 2011 Japan Tohoku tsunami on China Coast. Journal of Hydrodynamics, Serise B, 25(4):580-590 Ren Zhiyuan, Zhao Xi, Liu Hua. 2015. Dispersion effects on tsunami propagation in South China Sea. Journal of Earthquake and Tsunami, 9(5):1540001 Tang Liujuan, Titov V V, Moore C, et al. 2016. Real-time assessment of the 16 September 2015 Chile Tsunami and implications for near-field forecast. Pure and Applied Geophysics, 173(2):369-387 Watada S, Kusumoto S, Satake K. 2014. Traveltime delay and initial phase reversal of distant tsunamis coupled with the self-gravitating elastic Earth. Journal of Geophysical Research:Solid Earth, 119(5):4287-4310 Ye Lingling, Lay T, Kanamori H, et al. 2016. Rapidly estimated seismic source parameters for the 16 September 2015 Illapel, Chile Mw 8.3 Earthquake. Pure and Applied Geophysics, 173(2):321-332 Yu Fujiang, Yuan Ye, Zhao Lianda, et al. 2011. Evaluation of potential hazards from teletsunami in China:tidal observations of a teletsunami generated by the Chile 8.8 Mw earthquake. Chinese Science Bulletin, 56(11):1108-1116
点击查看大图
计量
- 文章访问数: 1119
- HTML全文浏览量: 37
- PDF下载量: 786
- 被引次数: 0