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Determination of focal depths of moderate earthquakes in Northeast Indian region using depth phase sPn

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Abstract

The precise focal depth of earthquakes is a crucial parameter for better characterising of complex tectonic zones, especially where seismogenic faults occur at different depths. Knowing accurate focal depth also allows recalculation of the equivalent magnitude for the reassessment of the mapping of the slip rate deficit and seismic hazard in the complex tectonic region. In the present study, we determined the focal depths using depth phases for earthquakes with magnitude 3.5 ≤ M ≤ 5.0 (except a few earthquakes with magnitude > 5) from 2011 to 2018 in the entire Northeast India region. We also validate the focal depths determined from the depth phases using point source waveform inversion. Our study area includes the NE-syntaxis arc to the eastern subduction belt, northern collision thrust belt and its foredeep/foreland area in the southern Brahmaputra plain and prominent Shillong plateau. For computing the focal depth, based on the tectonic setting and existing faults, we divided the region into five significant blocks, i.e. Himalaya collision zone, Assam Valley, Shillong Plateau, Eastern Himalaya Syntaxis, and Indo-Burmese Wedge. The focal depth variations in the five tectonic provinces suggested that the seismogenic depth in all the tectonic zones are shallow, i.e. 10–20 km. The shallow seismogenic zone is further supported by high seismic velocity. We also demarcated the geometry of mapped faults in Assam Valley and Shillong Plateau regions using cross-sectional seismicity plots. It is however noted that more data are needed for the Himalayan collision zone and Northeast syntaxis where multiple faults are involved.

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Fig. 1
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source depth below the epicentre of some selected events occurred during 2011–2018 in various tectonic zone (i.e. Himalayan Collision Zone; Assam Valley; Shillong Plateau; Eastern Himalayan syntaxis; Indo-Burmese Wedge). Colours scale represent the DC percentage. (B) Comparison of observed and synthetic waveforms of some selected events during 2011–2018 in various tectonic provinces (i.e. Himalayan Collision Zone; Assam Valley; Shillong Plateau; Eastern Himalayan syntaxis; Indo-Burmese Wedge (IBW)) computed using a waveform moment tensor inversion. Black and red waveforms represent the observed and synthetic waveforms, respectively. The blue numbers represent the variance reduction between the observed and synthetic waveforms

Fig. 7

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Data Availability

The earthquake catalogue can be accessed from the National Centre for Seismology (NCS) website at http://www.seismo.gov.in and the earthquake waveform data used in the present study corresponds to the National Seismological Network established by National Centre for Seismology, Ministry of Earth Sciences, New Delhi. The data are available on request from Director, NCS. All the Figures were made using MATLAB tool, Golden software and Generic mapping tools software (Wessel and Smith 1998).

References

  • Acharyya SK (2010) Tectonic evolution of Indo-Burma Range with Special reference to Naga-Manipur Hills. Mem Geol Soc Ind 75:25–43

    Google Scholar 

  • Aki K, Richards PG (1980) Methods of quantitative seismology, 2. W. H. Freeman and Co., San Francisco

    Google Scholar 

  • Alam M, Curray JR, Chowdhury MLR, Gani MR (2003) An overview of the sedimentary geology of the Bengal Basin in relation to the regional tectonic framework and basin-fill history. Sediment Geol 155:179–208

    Article  Google Scholar 

  • Arora BR, Prajapati SK, Saikia S, Bansal BK (2022) Crustal Structure of Northeast India as Evidenced by Receiver Function Imaging: Tectonic, Seismogenic and Geodynamic Implications Bull. of the Seismol. Soc. of Am (under review)

  • Baruah S, Duarah R, Yadav DK (1997) Pattern of seismicity in Shillong Mikir plateau and the orientation of principal compressive axis. J Geol Soc Ind 49:533–538

    Google Scholar 

  • Baruah S, Hazarika D, Kayal JR, Gogoi NK, Duarah R, Bora PK, Mukhopadyay S (2007) Seismotectonics and current state of stress in Chedrang valley and its vicinity—the rupture area of great Assam earthquake of June 12, 1897 (M = 8.7) from waveform and stress tensor inversion. Geophys Res (abstracts) 9:00127

    Google Scholar 

  • Benetatos C, Málek J, Verga F (2013) Moment tensor inversion for two micro-earthquakes occurring inside the Háje gas storage facilities, Czech Republic. J Seismol 17:557–577

    Article  Google Scholar 

  • Bhakuni SS, Luirei K, Kothyari GC, Imsong W (2017) Transverse tectonic structural elements across Himalayan mountain front, eastern Arunachal Himalaya, India: Implication of superposed landform development on analysis of neotectonics. Geomorphology 282:176–194

    Article  Google Scholar 

  • Bhattacharya SN, Ghose AK, Suresh G, Baidya PR, Saxena RC (1997) Source parameter of Jabalpur earthquake of 22 May 1997. Curr Sci 73(10):855–863

    Google Scholar 

  • Bhattacharya PM, Pujol J, Majumdar RK, Kayal JR (2005) Relocation of earthquakes in the northeast India region using joint hypocenter determination method. Curr Sci 89(8):1404–1413

    Google Scholar 

  • Bhattacharya PM, Mukhopadhyay S, Majumdar RK, Kayal JR (2008) 3-D seismic structure of the northeast India region and its implications for local and regional tectonics. J Asian Earth Sci 33:25–41

    Article  Google Scholar 

  • Bilham R (2006) Comment on “Interpreting the style of faulting and paleoseismicity associated with the 1897 Shillong, Northeast India Earthquake” by C.P. Rajendran et al Tectonics 25: TC2001. https://doi.org/10.1029/2005TC001893

  • Bilham R, England P (2001) Plateau ‘pop up’ in the great 1897 Assam earthquake. Nature 410:806–809

    Article  Google Scholar 

  • Bora PK, Sitaram MVD (2007) Signal durations and local richter magnitudes in Northeast India: an empirical approach. J Geol Soc India 70:323–338

    Google Scholar 

  • Brudzinski MR, Allen RM (2007) Segmentation in episodic tremor and slip all along Cascadia. Geology 35:907–910. https://doi.org/10.1130/G23740A.1

    Article  Google Scholar 

  • Chaudhury HM, Srivastava HN (1976) Seismicity and focal mechanism of some recent earthquakes in northeast India and neighbourhood. Ann Geophys 29:41–57

    Google Scholar 

  • Chen WP, Molnar P (1983) Focal depths of intracontinental and intraplate earthquakes and their implications for the thermal and mechanical properties of the lithosphere. J Geophys Res 88:4183–4214

    Article  Google Scholar 

  • Chen WP, Molnar P (1990) Source parameters of earthquakes and intraplate deformation beneath the Shillong Plateau and Northern Indo Burma ranges. J Geophys Res 95:12527–12552

    Article  Google Scholar 

  • Craig TJ, Heyburn R (2015) An enigmatic earthquake in the continental mantle lithosphere of stable North America. Earth Planet Sci Lett 425:12–23

    Article  Google Scholar 

  • Chong J, Ni SN, Zeng X (2010) Spl, an effective seismic phase for determining focal depth at near distance. Chin J Geophys-Chin Ed 53(11):2620–2630

    Google Scholar 

  • Curray JR, Emmel FJ, Moore DG, Raitt RW (1982) Structure, tectonics, and geological history of the northeastern Indian Ocean. In: Nairn AE, Stehli FG (eds) The ocean basins and margins-the Indian ocean, vol 6. Plenum, New York, pp 399–450

    Chapter  Google Scholar 

  • Curray JR, Moore DG, Lawver LA, Emmel FJ, Raitt RW, Henry M, Kieckhefer R (1979) Tectonics of the Andaman Sea and Burma. Geol Geophys Invest Contin Mar 29:189–198

    Google Scholar 

  • Dasgupta S, Nandy DR (1982) Seismicity and tectonics of Meghalaya plateau, N.E. India. In: Seventh symposium on earthquake engineering. University of Roorkee. pp 19–24

  • Das S, Mukhophahyay M, Nandy DR (2013) Active transverse features in the central portion of the Himalaya. Tectonophysics 136(3–4):255–264. https://doi.org/10.1016/0040-1951(87)90028-X

    Article  Google Scholar 

  • Devi EU, Rao NP, Kumar MR (2009) Modelling of sPn phases for reliable estimation of focal depth in northeastern India. Curr Sci 96(9):1251–1255

    Google Scholar 

  • Dreger D, Helmberger DV (1993) Determination of source parameters at regional distances with three-component sparse network data. J Geophys Res 98:8107–8125

    Article  Google Scholar 

  • Dube RK, Dattatrayam RS, Singh M, Srivastava HN (1986) Seismicity of northeast India with reference to the Cachar earthquake of December,1984. In: Proceedings of international symp on neotectonics in south Asia, SOI, Dehradun, Feb 1986

  • Engdahl E, Van der Hilst R, Buland R (1998) Global teleseismic earthquake relocation with improved travel times and procedures for depth determination. Bull Seismol Soc Am 88:722–743

    Google Scholar 

  • Evans P (1964) The tectonic framework of Assam. J Geol Soc Ind 5:80–96

    Google Scholar 

  • Gansser A (1964) Geology of the himalayas. Wiley, London, p 289

    Google Scholar 

  • Gomberg JS, Shedlock KM, Roecker SW (1990) The effect of S-wave arrival times on the accuracy of hypocenter estimation. Bull Seismol Soc Am 80(6A):1605–1628

    Article  Google Scholar 

  • Goswami TK, Mahanta BN, Mukherjee S, Syngai BR, Sarmah RK (2020) Orogen-transverse structures in the eastern Himalaya: Dextral Riedel shear along the Main Boundary Thrust in the Garu-Gensi area (Arunachal Pradesh, India), implication in hydrocarbon geoscience. Mar Pet Geol. https://doi.org/10.1016/j.marpetgeo.2020.104242

    Article  Google Scholar 

  • Gupta HK, Singh SC, Dutta TK, Saikia MM (1984) Recent investigations of North East India seismicity. In: Go G, Ma X-Y (eds) Proceedings of the international symposium on continental seismicity and earthquake prediction. Seismol Press, Beijing, 63–71

  • Guzman-Speziale M, Ni JF (1996) Seismicity and active tectonics of the western Sunda Arc. In: Yin A, Harrison TM (eds) The tectonic evolution of asia. Cambridge University Press, New York, pp 63–84

    Google Scholar 

  • Hauksson E (2000) Crustal structure and seismicity distribution adjacent to the Pacific and North America plate boundary in southern California. J Geophys Res 105:13,875-13,903

    Article  Google Scholar 

  • Havskov J, Voss PH, Ottemöller L (2020) Seismological observatory software: 30 Yr of SEISAN. Seismol Res Lett 91(3):1846–1852. https://doi.org/10.1785/0220190313

    Article  Google Scholar 

  • Ichikawa M, Srivastava HN, Drakopoulos JC (1972) Focal mechanism of earthquakes occurring in and around the Himalayan and Burmese mountain belts. Pap Meteor Geophys (tokyo) 23:149–162

    Article  Google Scholar 

  • Johnson SY, Alam AMN (1991) Sedimentation and tectonics of the Sylhet trough, Bangladesh. Geol Soc Am Bull 103:1513–1527

    Article  Google Scholar 

  • Kayal JR (1991) Earthquake prediction in Northeast India—a review. Pure Appl Geophys 136:297–313

    Article  Google Scholar 

  • Kayal JR (1998) Seismicity of Northeast India and surroundings—development over the past 100 years. J of Geophys 19(1):9–34

    Google Scholar 

  • Kayal J, Dapeng Z (1998) Three-dimensional seismic structure beneath Shillong Plateau and Assam valley, northeast India. Bull Seismol Soc Am 88(3):667–676

    Google Scholar 

  • Kayal JR, Banerjee B (1988) Anomalous behaviour of precursor resistivity in Shillong area, Northeast India. Geophys J Int 94:97–103

    Article  Google Scholar 

  • Kayal JR, De R (1991) Microseismicity and tectonics in North-east India. Bull Seismol Soc Am 81:131–138

    Article  Google Scholar 

  • Kayal JR (1996) Earthquake source process in northeast India: a review. J Himalayan Geol 17:53–69

    Google Scholar 

  • Kayal JR (2001) Microearthquake activity in some parts of the Himalaya and the tectonic model. Tectonophys 339:331–351

    Article  Google Scholar 

  • Kayal JR, Arefiev SS, Baruah S, Hazarika D, Gogoi N, Kumar A, Chowdhury SN, Kalita S (2006) Shillong plateau earthquakes in Northeast India region. Complex Tectonic Model Curr Sci 91:109–114

    Google Scholar 

  • Kayal JR (2008) Microearthquake seismology and seismotectonics of South Asia. Springer, Germany, p 503p

    Google Scholar 

  • Kayal JR, Gaonkar SG, Chakraborty GK, Singh OP (2004) Aftershocks and seismotectonic implications of the 13th September 2002 earthquake (MW 6.5) in the Andaman Sea Basin. Bull Seism Soc Am 94(1):326–333

    Article  Google Scholar 

  • Kayal JR, Arefiev SS, Baruah S, Hazarika D, Gogoi N, Gautam JL, Santanu B, Dorbath C, Tatevossian R (2012) Large and great earthquakes in the Shillong plateau–Assam valley area of northeast India region: pop-up and transverse tectonics. Tectonophys 532–535:186–192

    Article  Google Scholar 

  • Khattri K, Wyss M, Gaur VK, Saha SN, Bansal VK (1983) Local seismic activity in the region of the Assam gap, Northeast India. Bull Seism Soc Am 73:459–469

    Google Scholar 

  • Kikuchi M, Kanamori H (1991) Inversion of complex body waves; III. Bull Seismol Soc Am 81:2335–2350

    Article  Google Scholar 

  • Kumar A, Mitra S, Suresh G (2015) Seismotectonics of the Eastern Himalayan and indo-burma plate boundary systems. Tectonics 34:2279–2295. https://doi.org/10.1002/2015TC003979

    Article  Google Scholar 

  • Kundu B, Gahalaut VK (2012) Earthquake occurrence processes in the Indo-Burmese wedge and Sagaing fault region. Tectonophys 524–525(2012):135–146

    Article  Google Scholar 

  • Kundu A, Hazarika D, Hajra S, Singh AK, Ghosh P (2020) Crustal thickness and Poisson’s ratio variations in the northeast India-Asia collision zone: Insight into the Tuting-Tidding Suture zone, eastern Himalaya. J Asian Earth Sci 188:104099

    Article  Google Scholar 

  • Le Dain AY, Tapponnier P, Molnar P (1984) Active faulting and tectonics of Burma and surrounding regions. J Geophys Res 89(B1):453–472

    Article  Google Scholar 

  • Lienert BRE, Havskov J (1995) A computer program for locating earthquakes both locally and globally. Seism Res Lett 66:26–36

    Article  Google Scholar 

  • Lienert BR, Berg E, Frazer LN (1986) HYPOCENTER: an earthquake location method using centered, scaled, and adaptively least squares. Bull Seism Soc Am 76:771–783

    Article  Google Scholar 

  • Ma S, Atkinson GM (2006) Focal depths for small to moderate earthquakes (M ≥ 2.8) in western Quebec, southern Ontario, and northern New York. Bull Seismol Soc Am 96(2):609–623. https://doi.org/10.1785/0120040192

    Article  Google Scholar 

  • Ma S (2010) Focal depth determination for moderate and small earthquakes by modelling regional depth phases sPg, sPmP, and sPn. Bull Seismol Soc Am 100(3):1073–1088

    Article  Google Scholar 

  • Ma S, Motazedian D (2012) Studies on the June 23, 2010 north Ottawa M 5.2 earthquake and vicinity seismicity. J Seismo. https://doi.org/10.1007/s10950-012-9294-7

    Article  Google Scholar 

  • Maung H (1987) Transcurrent movements in the Burma-Andaman Sea region. Geology 15:911–912

    Article  Google Scholar 

  • Mishra OP (2011) Three-dimensional tomography of Northeast India and Indo-Burma region and its implications for Earthquake risks. In: National workshop on earthquake risk mitigation: strategy in the Northeast region 24–25 February 2011, Guwahati Assam, pp 40–54

  • Mitchell AHG (1981) Phanerozoic plate boundaries in mainland SE Asia, the Himalaya and Tibet. J Geol Soc Lond 138:109–122

    Article  Google Scholar 

  • Mitchell AHG, McKerrow WS (1975) Analogous evolution of the Burma orogen and the Scottish caledonides. Bull Geol Soc Am 86:305–315

    Article  Google Scholar 

  • Mitra S, Priestley K, Bhattacharyya AK, Gaur VK (2005) Crustal structure and earthquake focal depths beneath northeastern India and southern Tibet. Geophys J Int 160:227–248. https://doi.org/10.1111/j.1365-1246X.2004.02470.x

    Article  Google Scholar 

  • Monsalve G, Sheehan A, Rowe C, Rajaure S (2008) Seismic structure of the crust and the upper mantle beneath the Himalayas: evidence for eclogitization of lower crustal rocks in the Indian Plate. J Geophys Res 113:B08315. https://doi.org/10.1029/2007JB005424

    Article  Google Scholar 

  • Mukhopadhyay B, Acharyya A, Bhattacharyya D, Dasgupta S, Pande P (2011) Seismotectonics at the terminal ends of the Himalayan Arc. Geomat Nat Haz Risk 2(2):159–181. https://doi.org/10.1080/19475705.2010.536263

    Article  Google Scholar 

  • Murthy MVN, Talukdar SC, Bhattacharya AC (1969) The Dauki fault of Assam. Bull Oil Nat Gas Commun 6:57–64

    Google Scholar 

  • Nandy DR (2001) Geodynamics of Northeastern India and the adjoining region. ABC Publications Calcutta, pp 209

  • Nandy DR, Dasgupta S (1986) Application of remote sensing in regional studies- a case study in Northeastern part of India. Proc Int Sem Photogramet Remote Sens Dev Countries 1: T.4-P/6.1-T.4- P/6.4

  • Oldham RD (1899) Report on the great earthquake of the 12th June 1897. Mem Geol Sur India 29: 1–379 reprinted: 1981. Geol Sur of Ind Calcutta, 379p

  • Panthi A, Bhattarai J (2013) Seismicity pattern analysis in and around Shillong Great Earthquake of 1897. Himalayan Phys 5:36–38

    Article  Google Scholar 

  • Poddar MC (1950) The Assam earthquake of 15th August, 1950. Indian Miner 4:167–176

    Google Scholar 

  • Prieto GA, Froment B, Yu C, Poli P, Abercrombie R (2017) Earthquake rupture below the brittle-ductile transition in the continental lithospheric mantle. Sci Adv 3(3):e1602642. https://doi.org/10.1126/sciadv.1602642

    Article  Google Scholar 

  • Rajendran CP, Rajendran K, Duarah BP, Baruah S, Earnest A (2004) Interpreting the style of faulting and paleoseismicity associated with the 1897 Shillong, Northeast India, Earthquake: Implications for regional tectonism. Tectonics 23:1–12. https://doi.org/10.1029/2003TC001605

    Article  Google Scholar 

  • Rao NP, Kumar MR (1997) Uplift and tectonics of the Shillong Plateau, Northeast India. J Phys Earth 45:167–176

    Article  Google Scholar 

  • Sibson RH (1986) Earthquakes and rock deformation in crustal fault zones. Ann Rev Earth Planet Sci 14(1):149–175. https://doi.org/10.1146/annurev.ea.14.050186.001053

    Article  Google Scholar 

  • Singh MD, Kumar A (2013) Active deformation measurements at mishmi complex of Eastern Himalayan syntaxis. Int J Geosci. https://doi.org/10.4236/ijg.2013.44068

    Article  Google Scholar 

  • Smith-Konter BR, Sandwell DT, Shearer P (2011) Locking depths estimated from geodesy and seismology along the San Andreas Fault System: Implications for seismic moment release. J Geophys Res 116:B06401. https://doi.org/10.1029/2010JB008117

    Article  Google Scholar 

  • Socquet A, et al (2006) India and Sunda plates motion and deformation along their boundary in Myanmar determined by GPS. J Geophys Res 111

  • Sokos EN, Zahradník J (2008) ISOLA a FORTRAN code and a MATLAB GUI to perform multiple-point source inversion of seismic data. Comput Geosci 34:967–977

    Article  Google Scholar 

  • Suhendi C, Sudibyo MRP, Erlangga IF, Arbad AP (2019) Automatic event identification from tectonic earthquakes with modified Akaike information criterion (mAIC). IOP Conf Ser Earth Environ Sci 258:1–7. https://doi.org/10.1088/1755-1315/258/1/012037

    Article  Google Scholar 

  • Stein S, Wiens DA (1986) Depth determination for shallow teleseismic earthquakes: method and results. Rev Geophys 24:806–832

    Article  Google Scholar 

  • Stork AL, Selby ND, Heyburn R, Searle MP (2008) Accurate relative earthquake hypocenters reveal structure of the Burma subduction zone. Bull Seismol Soc Am 98(6):2815–2827

    Article  Google Scholar 

  • Tahara M, Shimizu H, Nakada M, Ito Y (2006) Focal depth distribution using sP depth phase and implications for plate coupling in the Hyuganada region, Japan. Phys Earth Planet Interiors 155(3–4):219–235

    Article  Google Scholar 

  • Tandon AN (1954) Study of the great Assam earthquake of August 1950 and its aftershocks. Ind J Met Geopghys 5:95–137

    Google Scholar 

  • Tandon AN, Srivastava HN (1974) Earthquake occurrence in India, Earthquake Engineering (Jai Krishna Volume), Sarita Prakashan, Meerut, 1–40

  • Tandon AN, Srivastava HN (1975) Focal mechanism of some recent Himalayan earthquakes and regional plate tectonics. Bull Seismol Soc Am 65:963–969

    Article  Google Scholar 

  • Thingbaijam KKS, Nath S (2008) Estimation of maximum earthquakes in Northeast India. Pure App Geophys 12:107–123

    Google Scholar 

  • Tillottson E (1953) The Great Assam Earthquake of 1950. The completion of papers on the Assam Earthquake of August 15, 1950, compiled by M.B. Ramchandra Rao, 94–96

  • Umino N, Hasegawa A, Matsuzawa T (1995) sP depth phase at small epicentral distances and estimated subducting plate boundary. Geophys J Int 120:356–366

    Article  Google Scholar 

  • Valdiya KS (1980) The two intracrustal boundary thrusts of the Himalaya. Tectonophysics 66:323–348

    Article  Google Scholar 

  • Vavrycuk V (2001) Inversion for parameters of tensile earthquakes. J Geophys Res 106(B8):16.339-16.355. https://doi.org/10.1029/2001JB000372

    Article  Google Scholar 

  • Yin A (2006) Cenozoic tectonic evolution of the Himalayan orogen as constrained by along-strike variation of structural geometry, exhumation history, and foreland sedimentation. Earth Sci Rev 76(1–2):1–131. https://doi.org/10.1016/j.earscirev.2005.05.004

    Article  Google Scholar 

  • Zhao LS, Helmberger DV (1994) Source estimation from broadband regional seismograms. Bull Seism Soc Am 84:92–104

    Google Scholar 

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Acknowledgements

The authors sincerely thank the Director, National Centre for Seismology for providing support for this work. The National Centre for Seismology (NCS), New Delhi, is highly acknowledged for establishing and maintaining the National Seismological Network in India. RK acknowledges the DST Inspire Division, Government of India for providing financial support through DST/INSPIRE Fellowship/2017/IF170905. We gratefully acknowledge the constructive review comments of two anonymous reviewers.

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  1. Indian Institute of Technology (Indian School of Mines), Dhanbad, India

    Rajkumar & Sanjit K. Pal

  2. National Centre for Seismology, Ministry of Earth Sciences, New Delhi, India

    Sanjay K. Prajapati

  3. Indian Meteorological Department, Former ADG, New Delhi, India

    H. N. Srivastava

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Rajkumar, Prajapati, S.K., Pal, S.K. et al. Determination of focal depths of moderate earthquakes in Northeast Indian region using depth phase sPn. Nat Hazards 114, 427–455 (2022). https://doi.org/10.1007/s11069-022-05396-7

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