Slip pulse and resonance of the Kathmandu basin during the 2015 Gorkha earthquake, Nepal

Galetzka, J.; Melgar, Diego; Genrich, J. F.; Geng, Jianghui; Owen, S. E.; Lindsey, E. O.; Xu, Xiaohua; Bock, Yehuda; Avouac, Jean Philippe; Adhikari, Lok Bijaya; Upreti, B. N.; Pratt-Sitaula, Beth; Bhattarai, Tara Nidhi; Sitaula, B. P.; Moore, A. W.; Hudnut, K. W.; Szeliga, Walter; Normandeau, Jim; Fend, M.; Flouzat, M.; Bollinger, Laurent; Shrestha, Prabin; Koirala, Bharat Prasad; Gautam, Umesh; Bhatterai, M.; Gupta, R.M.; Kandel, T.; Timsina, C.; Sapkota, Soma Nath; Rajaure, Sudhir; Maharjan, N.

doi:10.1126/science.aac6383

Cited by 320 publications

(305 citation statements)

References 34 publications

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“…The low-to-high gradient in the displacement of the aftershock is larger than the main shock suggesting there is a slip concentration at depth. Most of the displacement from the M w 7.3 aftershock occurs near the eastern end of the displacement from the main rupture suggesting it may have been triggered by a Coulomb stress concentration from the main shock [Galetzka et al, 2015].…”

Section: 1002/2015gl065385mentioning

confidence: 99%

“…This manuscript describes the new data and processing methods and more importantly refers to a web site where we present line-of-sight (LOS) data files for each track and frame described here for use in modeling studies [e.g., Wang and Fialko, 2015;Galetzka et al, 2015]. We will continue to provide postseismic LOS data as they become available.…”

Section: Introductionmentioning

confidence: 99%

“…The earthquake caused intense ground shaking throughout much of Nepal and parts of India and China, resulting in over 8000 deaths. Ground shaking in the Kathmandu basin was particularly intense as a result of its proximity to the main rupture area and the effects of basin amplification and directivity, causing many historical structures to collapse that had survived previous earthquakes [USGS, 2015, Galetzka et al, 2015.…”

Section: Introductionmentioning

confidence: 99%

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Line‐of‐sight displacement from ALOS‐2 interferometry: M_w 7.8 Gorkha Earthquake and M_w 7.3 aftershock

Lindsey

Natsuaki

et al. 2015

Geophysical Research Letters

186

109

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Interferometric synthetic aperture radar (InSAR) is a key tool for the analysis of displacement and stress changes caused by large crustal earthquakes, particularly in remote areas. A challenge for traditional InSAR has been its limited spatial and temporal coverage especially for very large events, whose dimensions exceed the typical swath width of 70–100 km. This problem is addressed by the ALOS‐2 satellite, whose PALSAR‐2 instrument operates in ScanSAR mode, enabling a repeat time of 2 weeks and a swath width of 350 km. Here we present InSAR line‐of‐sight displacement data from ALOS‐2/PALSAR‐2 observations covering the Mw 7.8 Gorkha, Nepal earthquake and its Mw 7.3 aftershock that were acquired within 1 week of each event. The data are made freely available and we encourage their use in models of the fault slip and associated stress changes. The Mw 7.3 aftershock not only extended the rupture area of the main shock toward the east but also left a 20 km gap where the fault has little or no coseismic slip. We estimate this unslipped fault patch has the potential to generate a Mw 6.9 event.

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Section: 1002/2015gl065385mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Line‐of‐sight displacement from ALOS‐2 interferometry: M_w 7.8 Gorkha Earthquake and M_w 7.3 aftershock

Lindsey

Natsuaki

et al. 2015

Geophysical Research Letters

186

109

View full text Add to dashboard Cite

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“…The rupture propagated eastwards, impacting areas up to ∼ 140 km from the epicenter, with additional large aftershocks concentrated near the eastern end of the mainshock rupture plane Galetzka et al, 2015). A rapid appraisal of the first available imagery suggested that landsliding occurred in an E-W swath located north of the Kathmandu Valley, covering a large proportion of western and central Nepal (∼ 12 000 km 2 ).…”

Section: Initial Landslide Identification Effortsmentioning

confidence: 99%

Satellite-based emergency mapping using optical imagery: experience and reflections from the 2015 Nepal earthquakes

Williams

Rosser

Kincey

et al. 2018

Nat. Hazards Earth Syst. Sci.

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Abstract. Landslides triggered by large earthquakes in mountainous regions contribute significantly to overall earthquake losses and pose a major secondary hazard that can persist for months or years. While scientific investigations of coseismic landsliding are increasingly common, there is no protocol for rapid (hours-to-days) humanitarian-facing landslide assessment and no published recognition of what is possible and what is useful to compile immediately after the event. Drawing on the 2015 M w 7.8 Gorkha earthquake in Nepal, we consider how quickly a landslide assessment based upon manual satellite-based emergency mapping (SEM) can be realistically achieved and review the decisions taken by analysts to ascertain the timeliness and type of useful information that can be generated. We find that, at present, many forms of landslide assessment are too slow to generate relative to the speed of a humanitarian response, despite increasingly rapid access to high-quality imagery. Importantly, the value of information on landslides evolves rapidly as a disaster response develops, so identifying the purpose, timescales, and end users of a post-earthquake landslide assessment is essential to inform the approach taken. It is clear that discussions are needed on the form and timing of landslide assessments, and how best to present and share this information, before rather than after an earthquake strikes. In this paper, we share the lessons learned from the Gorkha earthquake, with the aim of informing the approach taken by scientists to understand the evolving landslide hazard in future events and the expectations of the humanitarian community involved in disaster response.

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“…However, significant variations in the details of the rupture process, ranging from linearly distributed high-frequency sources with constant rupture velocity Meng et al 2016), to multistage rupture , and depth dependent variation in rupture velocity ) have been reported. Joint inversion of teleseismic waves, strong ground motion data, high-rate and static GPS data and SAR imagery (Galetzka et al 2015;Grandin et al 2015) pointed to a simple unilateral rupture with steady rupture velocity. The downdip limit of the rupture has been conjectured to coincide with the junction between the frontal flat and deeper steeply dipping ramp on the MHT.…”

Section: Introductionmentioning

confidence: 99%

The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust

Kumar¹,

Singh²,

Mitra³

et al. 2016

Geophys. J. Int.

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S U M M A R YThe 2015 Gorkha earthquake (M w 7.8) occurred by thrust faulting on a ∼150 km long and ∼70 km wide, locked downdip segment of the Main Himalayan Thrust (MHT), causing the Himalaya to slip SSW over the Indian Plate, and was followed by major-to-moderate aftershocks. Back projection of teleseismic P-wave and inversion of teleseismic body waves provide constraints on the geometry and kinematics of the main-shock rupture and source mechanism of aftershocks. The main-shock initiated ∼80 km west of Katmandu, close to the locking line on the MHT and propagated eastwards along ∼117 • azimuth for a duration of ∼70 s, with varying rupture velocity on a heterogeneous fault surface. The main-shock has been modelled using four subevents, propagating from west-to-east. The first subevent (0-20 s) ruptured at a velocity of ∼3.5 km s −1 on a ∼6 • N dipping flat segment of the MHT with thrust motion. The second subevent (20-35 s) ruptured a ∼18 • W dipping lateral ramp on the MHT in oblique thrust motion. The rupture velocity dropped from 3.5 km s −1 to 2.5 km s −1 , as a result of updip propagation of the rupture. The third subevent (35-50 s) ruptured a ∼7 • N dipping, eastward flat segment of the MHT with thrust motion and resulted in the largest amplitude arrivals at teleseismic distances. The fourth subevent (50-70 s) occurred by left-lateral strikeslip motion on a steeply dipping transverse fault, at high angle to the MHT and arrested the eastward propagation of the main-shock rupture. Eastward stress build-up following the mainshock resulted in the largest aftershock (M w 7.3), which occurred on the MHT, immediately east of the main-shock rupture. Source mechanisms of moderate aftershocks reveal stress adjustment at the edges of the main-shock fault, flexural faulting on top of the downgoing Indian Plate and extensional faulting in the hanging wall of the MHT.

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Slip pulse and resonance of the Kathmandu basin during the 2015 Gorkha earthquake, Nepal

Abstract: Movie S1Correction: In table S1, the displacement at station SNDL was reported erroneously. The correct displacement is: east, 0.047 ±0.002 m; north, -0.223 ±0.003 m; vertical, 0.003 ±0.003 m. The PDF has been corrected.

Cited by 320 publications

References 34 publications

Line‐of‐sight displacement from ALOS‐2 interferometry: M_w 7.8 Gorkha Earthquake and M_w 7.3 aftershock

Line‐of‐sight displacement from ALOS‐2 interferometry: M_w 7.8 Gorkha Earthquake and M_w 7.3 aftershock

Satellite-based emergency mapping using optical imagery: experience and reflections from the 2015 Nepal earthquakes

The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust

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Slip pulse and resonance of the Kathmandu basin during the 2015 Gorkha earthquake, Nepal

Abstract: Movie S1Correction: In table S1, the displacement at station SNDL was reported erroneously. The correct displacement is: east, 0.047 ±0.002 m; north, -0.223 ±0.003 m; vertical, 0.003 ±0.003 m. The PDF has been corrected.

Cited by 320 publications

References 34 publications

Line‐of‐sight displacement from ALOS‐2 interferometry: Mw 7.8 Gorkha Earthquake and Mw 7.3 aftershock

Line‐of‐sight displacement from ALOS‐2 interferometry: Mw 7.8 Gorkha Earthquake and Mw 7.3 aftershock

Satellite-based emergency mapping using optical imagery: experience and reflections from the 2015 Nepal earthquakes

The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust

Contact Info

Product

Resources

About

Line‐of‐sight displacement from ALOS‐2 interferometry: M_w 7.8 Gorkha Earthquake and M_w 7.3 aftershock

Line‐of‐sight displacement from ALOS‐2 interferometry: M_w 7.8 Gorkha Earthquake and M_w 7.3 aftershock