基于密集地震台网的大震震源研究及其在地震防灾中的应用.pdf

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 Dun Wang ( ) In collaboration with: Hitoshi Kawakatsu, Jim Mori, Kazuki Koketsu, Takuto Maeda, Hiroshi Tsuroka, Jiancang Zhunag, Lihua Fang, and Qiang Yao School of Geosciences, China University of Geosciences @ Wuhan, China; CEA; Earthquake Research Institute, The University of Tokyo, Japan; Disaster Prevention Research Institute, Kyoto University, Japan   1
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  1. Wang, D., and A., Hutko, Relative relocations of the North Korean nuclear tests from 2006 to 2017 using the Hi-net array in Japan. Geophysical Research Letters (in press). 2. Wang, D.Kawakatsu, H., Zhuang, J., Mori, J., Maeda, T., Tsuruoka, H., & Zhao, X., Automated determination of magnitude and source length of large earthquakes using backprojection and P wave amplitudes. Geophysical Research Letters, 44(11), 5447-5456, 2017. 3. Wang, D.,H., Kawakatsu, J., Mori,B. Ali, Z.K., Ren, and X.L., Shen, Back-Projection Analyses from Four Regional Arrays for Rupture Over a Curved Dipping Fault: The Mw 7.7 September 24, 2013 Pakistan Earthquake, J. Geophys. Res. Solid Earth,121,1948–1961, 2016. 4. Wang, D.,J., Mori, and T., Uchide, Supershear Rupture on Conjugate Faults for the Mw8.6 Off Northern Sumatra, Indonesia Earthquake of April 11, 2012,Geophys. Res. Lett., Vol. 39, L21307, pp.1-5, November, 2012. 5. Wang, D.,J., Mori, and K., Koketsu, Fast Rupture Propagation for Large Strike-slip Earthquakes, Earth and Planetary Science Letters, Volume 440, Pages 115–126, 15 April, 2016. 6. Wang, D., Takeuchi, N., Kawakatsu, H., and Mori, J., Estimating high frequency energy radiation of large earthquakes by image deconvolution back-projection. Earth and Planetary Science Letters,449, 155-163, 2016. 7. Wang, D. and J., Mori, The 2010 Qinghai, China Earthquake: A Moderate Earthquake with Supershear Rupture, Bull. Seismol. Soc. Am., Vol. 102, No.1, pp. 301-308, February, 2012. 8. Wang, D. and J., Mori, Frequency-dependent energy radiation and fault coupling for the 2010 Mw8.8 Maule, Chile and 2011 Mw9.0 Tohoku, Japan earthquakes, Geophys. Res. Lett., Vol. 38, L22308, pp.1-6, November, 2011.   
   M > 8 earthquakes since 1973 (USGS) Methods Back Projection Search a grid of points to determine the best location for the source of seismic radiation in each designated time window of interested waves. Aligned waveforms Stacked waveforms Large stacked amplitude Modefied from Hutko Small stacked amplitude 5 (Ishii et al., 2005, Nature) 
   Image Deconvolution Back-Projection (IDBP)    (Wang et al., 2016b, EPSL)  
 Frequency-dependent Energy Radiation Rupture Speed Frequency-dependent Energy Radiation 2015 M 7.8 Nepal Eq (Wang and Mori, 2016, BSSA) (Fletcher et al., 2014, JGR) (Wang Mori, 2010 M 8.8 Chile andand 2011 MGRL, 9.0Tohoku SSA 2012 Annual Meeting ,2011) Sanearthquakes Diego, California 17-19 April 2012 (Yao et al., 2013, PNAS) Frequency-dependent Energy Radiation 3.Resolution Tests (Lay et al., 2012, JGR) SSA 2012 Annual Meeting , San Diego, California 17-19 April 2012 Average rupture speeds of recent large earthquakes 10 (Wang et al., EPSL, 2016a) 2008 M 7.9 Wenchuan earthquake Rupture speeds derived from back-projection using EUR data and Alaska regional array (blue, by Du et al., 2009) and strong motion inversion (black triangles, by Zhang et al., 2012) for the 2008 M 7.9 Wenchuan earthquake. 11 (Wang et al., EPSL, 2016a) Rupture propagation for five large strike-slip earthquakes 12 (Wang et al., EPSL, 2016a) 
   Automated Determination of Magnitude (Mdt) of Large Shallow Earthquakes in Japan using Real Time Seismic data recorded in China and across the Globe (GSN) Motivation 30 year Probabilities North Sanriku-oki ~M8 0.2 to 10% Off Sanriku South Sanriku-oki ~M7.7 80 to 90% Off Miyagi ~M7.5 > 90% Off Fukushima ~M7.4 7% Off Ibaraki ~M6.7 – M7.2 90% Expected Earthquake Sources 50 to 150 km segments M6.7 to 8.2 (Headquarters for Earthquake Research Promotion, Japan) Sanriku to Boso M8.2 (plate boundary) 20% Sanriku to Boso M8.2 (Intraplate) 4-7% (Concluded by Jim Mori) Earthquake much bigger than expected ! Off Sanriku Expected Earthquake Sources 50 to 150 km segments M6.7 to 8.2 (Headquarters for Earthquake Research Promotion) 2011 Tohoku Earthquake 500 km long fault, M 9.0 (Aftershock map from USGS) The 2011M 9.0 Tohoku, Japan earthquake The 2011 M 9.0 Tohoku earthquake Mw Source extent source duration asperity locations 72 hours Origin Time 10 min 100 min Magnitude 5-13 min after O.T. Mwp 7.9 USGS 32 min after O.T. Mw 8.9 USGS W phase Tsunami warning 4 -24 min after O.T. warning based on Mjma 7.9 (JMA) Tsunami hit the nearest coast (JMA), and Tsunami Warning extended Source extent
1000 min 2h 10h 7 h after O.T. Mw 9.1 GCMT Slip models Kramer, 1996 (Qiang Yao, 2018) A new magnitude scale Mdt (Displacement & Time
? ? ? Dun Wang & Tatsuhiko Hara ? Locations of earthquakes analysed in this study (Depth <= 60 km; Magnitude
Mww >= 7.0; Distance (to station HMNH) = 15 - 120 deg.; 2004-2014). Dashed lines represent the distances to the Hi-net center (black triangle). Color indicates the distance to Hi-net (red, 10-30o; yellow, 3085o; purple, 85-100o; black, 100-120o) From global stations Source duration derived from back-projection Mw (GCMT) Maximum P displacement Maximum displacement of P wave From Hi-net Epicentre distance Time (s) A new magnitude scale- Mdt (Displacement & Time
Dun Wang & Tatsuhiko Hara) 0.55 0.67 1.01 5.55 Distance range of GSN stations Automated determination of magnitude and source Robust with aextent few 60-85 global stations 50-80 40-70 10-40 Duration & GSN stations in a series of distance ranges with respect to the epicenters. Color indicates distance ranges to the Hi-net center. 30-60 Inset panel shows the frequency content of the difference between magnitudes estimated from GCMT and our system for earthquakes that were located 30-85o to Hi-net. 20-50 10-40 (Wang et al., GRL, 2017) Magnitude Variation with elapsed time Source extent and energy radiation The September 24, 2013, Mw 7.7 Pakistan earthquake (a) Locations of aftershocks that occurred one week following the September 24, 2013, Mw 7.7 earthquake. The red star indicates the epicentre (USGS). (b) White and red shaded squares indicate health facilities which were undamaged and (Wang et al., JGR, 2016) damaged, respectively (http://www.ndma.gov.pk). The September 24, 2013, Mw 7.7 earthquake Data: Hi-net, band-pass filtered 1.0-10.0 Hz
Wang et al., JGR, 2016      
Avouac et al., 2014, EPSL  M>= 7.0 earthquakes in Japan from 2008 to 2016 Mdt of the M>= 7.0 earthquakes in Japan 0.55 0.67 1.01 5.55 The 11 March 2011 Tohoku, Japan earthquake Station correction database Automated back-projection in real time doesn’t need the earthquake catalog Timing How fast can this method offer information for the Mw, source extent, asperity locations now? Epicenter distance (degree) 10 30 50 90 Travel Time (minute) 2-3 6 9 13 Epicenter distance (km) 1111.2 3335.7 5556 10000.8 Source extent, IRIS, 60 min after O. T. of earthquakes W-phase inversion, ~30 min, Moment magnitude Magnitude of the 23 January 2018 M7.9 Alaska Eq Stations used in back-projection The earthquake sequence Global stations used for P displacements Magnitude of the 23 January 2018 M7.9 Alaska Eq Maximum displacements of P waves Source duration PTWC,NOAA/NEI C M 8.0-8.2 in the first hour, became M7.9 around 2 hours after the origin time. Future Work: For global earthquakes M >= 7.5, Depth < 60 km, USGS catalog (1970-2014)