Eric Fielding, Cunren Liang, Mong-Han Huang, Sang-Ho Yun

National Aeronautics and Space Administration Imaging Coseismic Deformation from Large Thrust Earthquakes on the Edges of the Tibetan Plateau with Geodetic and Seismic Data Eric Fielding, Cunren Liang, Mong-Han Huang, Sang-Ho Yun Jet Propulsion Laboratory, Caltech* Han Yue, Mark Simons Caltech Sergey Samsonov Natural Resources Canada Simran Sangha#, Gilles Peltzer#, Susan Owen, Angelyn

Tajikistan (2015)

Manyi (1997) Kokoxili (2001) Yutian (2008) Kashmir (2005)

Wenchuan (2008)

Gorkha (2015)

Thrust on edges, strike-slip and normal inside plateau 73˚ 74˚ 2005 Kashmir earthquake 35˚ 35˚

• Kashmir Himalayas near Hazara Syntaxis

• 8th October 2005, Mw 7.6

>80,000 fatalities • 34˚ 34˚ • epicenter near Muzaﬀarabad, Pakistan

meters surface ruptures along 6000 • 4000 Balakot-Bagh fault system 2000 0 73˚ 74˚ Kashmir static slip inversion

• Three tracks Envisat pixel oﬀsets: slant-range and azimuth

• Optimized geometry of single rectangular fault

• Strike 323°, dip 30°N, Depth ( km ) 100 km long NW (number of 2 km patches) Slip • All slip in upper 10 km (m)

Pathier, E., Fielding, E. J., Wright, T. J., Walker, R., Parsons, B. E., and Hensley, S., 2006, Displacement ﬁeld and slip distribution of the 2005 Kashmir earthquake from SAR imagery: Geophysical Research Letters, v. 33, no. 20, p. L20310, doi:20310.21029/22006GL027193. Kashmir 3D displacements

• Combination of Envisat pixel oﬀsets

• Estimated 3D displacements averaged 5 x 5 km

• Colors show vertical (max 6 m uplift)

• arrows horizontal displacement (max 4 m)

• High Himalayas uplifted 2008 Wenchuan 102˚ 104˚ 106˚

Earthquake 34˚ 34˚ • eastern Sichuan, China

Qingchuan • 12 May 2008, Mw 7.9 Pingwu Guangyuan

32˚ Beichuan 32˚ >70,000 fatalities MaoXian Jiangyou • Lixian Wenchuan Mianyang

Yingxiu Deyang • epicenter at SW end Dujiangyan Dayi Chengdu

Kangding • surface ruptures 250 km along30˚ Ya’an 30˚ mountain front Elevation (meters) • steep Longmen Shan 4000 2000 mountains at east edge of 0 Tibetan plateau 28˚ 102˚ 104˚ 106˚ 101˚ 102˚ 103˚ 104˚ 105˚ 106˚ 107˚ ALOS PALSAR 35˚ ALOS PALSAR

interferometry 38° look 34˚

• six paths cover rupture, plus two at ends 33˚ Qingchuan Pingwu Guangyuan ROI_pac processing & • 32˚ Beichuan SNAPHU unwrapping MaoXian Jiangyou Lixian Wenchuan Mianyang

coherence lost in steep Yingxiu Deyang • 31˚ Dujiangyan

slopes with longer Dayi Chengdu baselines, and where Kangding displacements large 30˚ Ya’an LOS change • artifact waves cause up to meters 1 m of range change 29˚ 1.0 variations 0.0 −1.0 Complex fault geometry approximated with ﬁve planar fault segments

1155 InSAR-only view to NE slip inversion with (cm) low smoothing applied 0 −10 550 −20 −30 500 3650 450 3600 UTM km 3550 400 3500 350 3450 0

Fielding, E. J., Sladen, A., Li, Z., Avouac, J.-P., Bürgmann, R., and Ryder, I., 2013, Kinematic fault slip evolution source models of the 2008 M7.9 Wenchuan earthquake in China from SAR interferometry, GPS and teleseismic analysis and implications for Longmen Shan tectonics: Geophysical Journal International, v. 194, no. 2, p. 1138-1166. Joint GPS-InSAR-seismic inversion • eight PALSAR ascending, 4IM+1WS ASAR descending • Five fault segments • deep Pengguan fault 32° • Beichuan fault 52° (S), 50° (mid) 58° (N) • Hanwang fault 34° • coseismic GPS from Shen et al. (2009) (black and gray arrows, obs. & pred.) • leveling compare only red & green: predicted horizontal & vertical Joint InSAR-GPS-seismic inversion Hanwang NE fault SW Beichuan

hypocenter Pengguan fault • hypocenter on deep fault segment, propagated upward • most slip shallow <10 km, onto Beichuan fault except near Wenchuan & NE • early slip nearly pure thrust, • landslides of Beichuan area later slip much more strike- over largest slip slip 2015 Gorkha Earthquake

Nepal Himalayas near • 84˚E 85˚E 86˚E 87˚E 29˚N China Kathmandu Elevation, km Nepal Fault slip, m 8 JMSM 6 4 4 2 0 • 25th April 2015, Mw 7.8 DNSG 0 CHLM Mw 7.8 m 1.5 China 3.0m 28˚N 5.5m Nepal SYB • >9,000 fatalities KKN4 Kathmandu Bharatpur NAST 1.5 Nepal Mw 7.3 India • epicenter near Gorkha, SNDL Horizontal motion GPS Main Frontal Thrust Nepal 27˚N RMTE City/town 100 cm Mb>6 1cm 5

Yue, H., Simons, M., Duputel, Z., Jiang, J., Fielding, E., Liang, C., Owen, S., Moore, A., Riel, B., Ampuero, J.-P., and Samsonov, S. V., 2016, in revision, Depth varying rupture properties during the 2015 Mw 7.8 Gorkha (Nepal) earthquake: Tectonophysics. 85˚E 86˚E 85˚E 86˚E 29˚N Gorkha input ALOS-2 ALOS-2

28˚N Heading

data ASC LOS Δ =224 day ig Δig=70 day Δ =77 day ps Δps=7 day LOS 27˚N 29˚N • Three ALOS-2, ALOS-2 Sentinel-1a Sentinel-1, two 28˚N LOS RADARSAT-2 1.0 DSC LOS Δ =70 day ig Δig=12 day interferograms Δ =8 day Heading ps Δps=4 day 27˚N 0.0 29˚N RADARSAT-2 two RADARSAT-2 RADARSAT-2 • −1.0 Displacement, m

azimuth pixel oﬀsets 28˚N LOS DSC LOS

Δig=24 day Δig=24 day

Heading Δps=11 day Δps=4 day 27˚N • 6 stations high-rate 29˚N GPS displacements RADARSAT-2 RADARSAT-2

28˚N Azimuth • 38 teleseismic body DSC AZO Δig=24 day Δig=24 day

Δps=11 day Δps=4 day wave records 27˚N 85˚E 86˚E 85˚E 86˚E Gorkha slip inversion • Uniform dip angle of 6° SE NW Mean slip of posterior model samples Bayesian 0 Slip, m 6 • 20 10 kinematic Depth, km inversion 0 12 (AlTar) −20 14 mean of • −40 16 posterior Along dip distance, km distribution −120 −80 −40 0 Along strike distance, km • Slip below 10 km depth Gorkha vertical deformation

84˚ 85˚ 86˚ 87˚ 88 • ALOS-2 ScanSAR

interferogram 29˚ LOS • Descending line-of- TIBET sight (LOS) perpendicular to 28˚ M7.8 horizontal Kathmandu M7.3 • InSAR phase only sees displacement vertical component (meters) NEPAL 27˚ 1.2

0.0 50 cm INDIA • High Himalayas −1.2 dropped down as much as 1.2 m Comparison conclusions

• Thrust quakes on shallowly dipping detachments down-drop main mountains (Gorkha quake; slip > 10 km depth) • Steeper reverse-fault quakes uplift mountains (Kashmir and Wenchuan; slip <10 km) • Long-term deformation likely involves both types of quakes • Shallow ruptures that reach surface cause more damage to buildings and infrastructure (order of magnitude more deaths for Kashmir and Wenchuan)