@article{MTMT:31770543, title = {Seismic hazard and risk in Bhutan}, url = {https://m2.mtmt.hu/api/publication/31770543}, author = {Stevens, Victoria L. and De Risi, Raffaele and Le Roux-Mallouf, Romain and Drukpa, Dowchu and Hetényi, György}, doi = {10.1007/s11069-020-04275-3}, journal-iso = {NAT HAZARDS}, journal = {NATURAL HAZARDS}, volume = {104}, unique-id = {31770543}, issn = {0921-030X}, abstract = {We present the first modern seismic hazard and risk assessment in the Bhutan Himalaya. We used a fault-based probabilistic seismic hazard analysis based on fault locations, slip-rates, and paleoseismic earthquake data. We worked with two seismic intensity measures: the peak-ground acceleration (PGA) and Modified Mercalli Intensity (MMI). We extend the hazard analysis to risk by using local building distribution data and making various assumptions about building distribution and fragility. We find, unsurprisingly, that the Main Himalayan Thrust (MHT) is the primary source of hazard, with oblique strike-slip faults cutting across and beneath the Himalaya, and extensional grabens on the northern edge of Bhutan a secondary hazard. The hazard is highest in the southern part of Bhutan where the MHT is shallow, and site conditions lead to amplification of shaking. The risk does not reflect the hazard solely, but also the distribution of exposure, which is concentrated in the cities. We also simulated the 1714 M(W)8 earthquake, producing 10,000 possible shakemaps in terms of PGA and MMI; we find that many locations could experience PGA values of over 1 g, and on average, up to 18% of the Bhutanese population could be affected. Refining the probable frequency of larger events on the MHT in this region, developing local ground motion prediction equations, creating tailored vulnerability models for typical Bhutanese buildings, and improving the exposure mapping would most improve the hazard and risk results shown here. The existing building code of Bhutan, adopted from the Indian Seismic Zonation of 2002 (BIS-1893 in Indian standard criteria for earthquake resistant design of structures, Part 1-General provisions and buildings, New Delhi, 2002), uses a PGA of 0.36 g uniformly applied across the entire country. Our study, however, presents a non-uniform hazard level across the country and thus questions the relevancy of the current code of construction practices in the country.}, keywords = {earthquakes; seismic hazard; Himalaya; Bhután; SEISMIC RISK}, year = {2020}, eissn = {1573-0840}, pages = {2339-2367}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:31439083, title = {Seismology at School in Nepal: A Program for Educational and Citizen Seismology Through a Low-Cost Seismic Network}, url = {https://m2.mtmt.hu/api/publication/31439083}, author = {Subedi, Shiba and Hetényi, György and Denton, Paul and Sauron, Anne}, doi = {10.3389/feart.2020.00073}, journal-iso = {FRONT EARTH SC-SWITZ}, journal = {FRONTIERS IN EARTH SCIENCE}, volume = {8}, unique-id = {31439083}, abstract = {Nepal, located above the convergent India-Eurasia plate boundary, has repeatedly experienced devastating earthquakes. During the 2015 magnitude 7.8 Gorkha earthquake, an often-reported experience was that people were not aware of the threatening seismic hazard and had an insufficient level of preparedness. An important source of the problem is that earthquake-related topics are not part of the school curriculum. Earthquake education reaching a broad group of the population early in their lives is therefore strongly needed. We established an initiative in Nepal to introduce seismology in schools, with a focus on education and citizen seismology. We have prepared educational materials adapted to the Nepali school system, which we distributed and also share on our program's website: . In selected schools, we also installed a low-cost seismometer to record seismicity and to allow learning-by-doing classroom activities. Our approach was very well received and we hope it will help make earthquake-safe communities across Nepal. The seismic sensor which we installed in schools is a Raspberry Shake 1D (RS1D), this was selected based on its performance in laboratory tests and suitability for the field conditions. At a test site in Switzerland we were able to record magnitude 1.0 events up to 50 km distance with a RS1D. In Nepal, 22 such seismometers installed in schools create the Nepal School Seismology Network providing online data openly. The seismometer in each school allows students to be informed of earthquakes, visualize the respective waveforms, and estimate the distance and magnitude of the event. For significant local and regional events, we provide record sections and network instrumental intensity maps on our program's website. In 6 months of network operation, more than 194 local and teleseismic earthquakes of M >= 4 have been recorded. From a local and a global catalog, complemented with our own visual identifications, we have provided an earthquake wave detectability graph in distance and magnitude domain. Based on our observations, we have calibrated a new magnitude equation for Nepal, related to the epicentral distance D [km] and to the observed peak vertical ground velocity PGV(V) [mu m/s]. The calibration is done to best fit local catalog magnitudes, and yields the following equation: M = 1.05 x log(10)(PGV(V)) + 1.08 x log(10)(D) + 0.75.}, keywords = {seismic hazard; earthquake magnitude; Nepal; citizen science; educational seismology}, year = {2020}, eissn = {2296-6463}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:31098644, title = {Source mechanism of a lower crust earthquake beneath the Himalayas and its possible relation to metamorphism}, url = {https://m2.mtmt.hu/api/publication/31098644}, author = {Alvizuri, Celso and Hetényi, György}, doi = {10.1016/j.tecto.2019.06.023}, journal-iso = {TECTONOPHYSICS}, journal = {TECTONOPHYSICS}, volume = {769}, unique-id = {31098644}, issn = {0040-1951}, abstract = {The nature of deep-crustal, intermediate and deep-focus earthquakes and their relation to metamorphic reactions is a topic of debate. Here we seek to better understand a possible link between the earthquake process and metamorphism by analyzing the mechanism of ongoing deep-crustal earthquakes. We focus on a region in the Himalayas with observed seismicity at depths expected to experience active eclogite-facies metamorphism and dehydration reactions. There are few permanent seismic stations in the region, therefore we use waveform data from a temporary seismic array deployment. We find two earthquakes with magnitude and station coverage adequate for moment tensor inversion. For a given earthquake we estimate its seismic full moment tensors (and magnitude) together with uncertainties using all available waveforms. For the largest earthquake (Mw 3.7) we obtain a best-fitting moment tensor and uncertainties that show a double-couple with a tensional crack component. In the context of geological records that document similar processes, and of laboratory experiments conducted at spatial scales that are 5-6 orders of magnitude smaller, this mechanism may be related to dehydration-driven stress changes triggering slight crack opening, and ambient stresses favoring slip along a fault.}, keywords = {earthquake; METAMORPHISM; Himalaya; seismic moment tensor; Uncertainty estimates; Dehydration embrittlement}, year = {2019}, eissn = {1879-3266}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:30592176, title = {Stress transfer and connectivity between the Bhutan Himalaya and the Shillong Plateau}, url = {https://m2.mtmt.hu/api/publication/30592176}, author = {Grujic, Djordje and Hetényi, György and Cattin, Rodolphe and Baruah, Saurabh and Benoit, Angelique and Drukpa, Dowchu and Saric, Adi}, doi = {10.1016/j.tecto.2018.07.018}, journal-iso = {TECTONOPHYSICS}, journal = {TECTONOPHYSICS}, volume = {744}, unique-id = {30592176}, issn = {0040-1951}, abstract = {Within the northern Indian Plate, the Shillong Plateau is a peculiar geodynamic terrane, hosting significant seismic activity outboard the Himalayan belt. This activity is often used as an argument to explain apparent reduced seismicity in the Bhutan Himalayas. Although current geophysical and geodetic data indicate that the Bhutan Himalayas accommodate more deformation than the Shillong Plateau, we aim to quantify the extent to which the two geodynamic regimes are connected and potentially interact through stress transfers. We compiled a map of major faults and earthquakes in the two regions and computed co-seismic stress transfer amplitudes. Our results indicate that the Bhutan Himalayas and the Shillong Plateau are less connected than previously suggested. Major earthquakes in either of the two regions mainly affect transverse faults connecting them, causing up to similar to 40 bar Coulomb stress change; however, this effect is clearly less on thrust faults of the either region (up to 1 bar only). The M-w 8.25 1897 Assam earthquake that affected the Shillong Plateau did not cause a stress shadow on the Main Himalayan Thrust in Bhutan as previously suggested. Similarly, the M-w 8 +/- 0.5 1714 Bhutan earthquake had negligible impact on stress accumulation on thrust faults bounding the Shillong Plateau. Furthermore, the main process shaping the regional stress patterns continues to be interseismic loading with complex boundary conditions in a diffuse deformation field involving the Bengal Basin and Indo-Burman Ranges. While both the Bhutan Himalayas and the Shillong Plateau exhibit a compressional regime, their stress evolutions are more weakly connected than hypothesized. Although our modelling suggests lateral increase in stress interactions, from west (less) to east (more), in the Bhutan Himalayas, a clearer picture will only emerge with better constrained fault geometries, slip rates, crustal structure, and seismicity catalogues in the entire region of distributed deformation.}, keywords = {STRESS TRANSFER; seismotectonics; SHILLONG PLATEAU; Coulomb stress change; Bhutan Himalayas}, year = {2018}, eissn = {1879-3266}, pages = {322-332}, orcid-numbers = {Grujic, Djordje/0000-0002-5833-8843; Hetényi, György/0000-0001-9036-4761} } @article{MTMT:30482510, title = {Imaging the Moho and the Main Himalayan Thrust in Western Nepal With Receiver Functions}, url = {https://m2.mtmt.hu/api/publication/30482510}, author = {Subedi, Shiba and Hetényi, György and Vergne, Jerome and Bollinger, Laurent and Lyon-Caen, Helene and Farra, Veronique and Adhikari, Lok Bijaya and Gupta, Ratna Mani}, doi = {10.1029/2018GL080911}, journal-iso = {GEOPHYS RES LETT}, journal = {GEOPHYSICAL RESEARCH LETTERS}, volume = {45}, unique-id = {30482510}, issn = {0094-8276}, abstract = {The crustal structure of Western Nepal is studied for the first time by performing receiver function analysis on teleseismic waveforms recorded at 16 seismic stations. The Moho geometry is imaged as it deepens from similar to 40-km depth beneath the foothills and the Lesser Himalaya to similar to 58-km depth beneath the Higher Himalayan range. A midcrustal low-velocity zone is detected at similar to 15-km depth along similar to 55-km horizontal distance and is interpreted as the signature of fluids expelled from rocks descending in the footwall of the Main Himalayan Thrust. Our new image allows structural comparison of the Moho and of the Main Himalayan Thrust geometry along-strike of the Himalayas and documents long-wavelength lateral variations. The general crustal architecture observed on our images resembles that of Central Nepal; therefore, Western Nepal is also expected to be able to host large (M-W>8) megathrust earthquakes, as the 1505 CE event.}, year = {2018}, eissn = {1944-8007}, pages = {13222-13230}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761; Vergne, Jerome/0000-0003-1731-9360; Lyon-Caen, Helene/0000-0002-6331-0108} } @article{MTMT:3273926, title = {Seismotectonics of Bhutan: Evidence for segmentation of the Eastern Himalayas and link to foreland deformation}, url = {https://m2.mtmt.hu/api/publication/3273926}, author = {Diehl, T and Singer, J and Hetényi, György and Grujic, D and Clinton, J and Giardini, D and Kissling, E}, doi = {10.1016/j.epsl.2017.04.038}, journal-iso = {EARTH PLANET SC LETT}, journal = {EARTH AND PLANETARY SCIENCE LETTERS}, volume = {471}, unique-id = {3273926}, issn = {0012-821X}, abstract = {The instrumental record of Bhutan is characterized by a lower seismicity compared to other parts of the Himalayan arc. To understand this low activity and its impact on the seismic hazard, a seismic network was installed in Bhutan for 22 months between 2013 and 2014. Recorded seismicity, earthquake moment tensors and local earthquake tomography reveal along-strike variations in structure and crustal deformation regime. A thickened crust imaged in western Bhutan suggests lateral differences in stresses on the Main Himalayan Thrust (MHT), potentially affecting the interseismic coupling and deformation regime. Sikkim, western Bhutan and its foreland are characterized by strike-slip faulting in the Indian basement. Strain is particularly localized along a NW–SE striking mid-crustal fault zone reaching from Chungthang in northeast Sikkim to Dhubri at the northwestern edge of the Shillong Plateau in the foreland. The dextral Dhubri–Chungthang fault zone (DCF) causes segmentation of the Indian basement and the MHT between eastern Nepal and western Bhutan and connects the deformation front of the Himalaya with the Shillong Plateau by forming the western boundary of the Shillong block. The Kopili fault, the proposed eastern boundary of this block, appears to be a diffuse zone of mid-crustal seismicity in the foreland. In eastern Bhutan we image a seismogenic, flat portion of the MHT, which might be either related to a partially creeping segment or to increased background seismicity originating from the 2009 MW6.1 earthquake. In western-central Bhutan clusters of micro-earthquakes at the front of the High-Himalayas indicate the presence of a mid-crustal ramp and stress buildup on a fully coupled MHT. The area bounded by the DCF in the west and the seismogenic MHT in the east has the potential for M7–8 earthquakes in Bhutan. Similarly, the DCF has the potential to host M7 earthquakes as documented by the 2011 Sikkim and the 1930 Dhubri earthquakes, which were potentially associated with this structure. © 2017 Elsevier B.V.}, keywords = {DEFORMATION; TOMOGRAPHY; Seismology; earthquakes; Image segmentation; seismicity; faulting; Fault zone; Geophysics; Buildings; Strike-slip faults; Bhután; Main himalayan thrusts; Main Himalayan Thrust; SHILLONG PLATEAU; local earthquake tomography; Dhubri–Chungthang fault zone}, year = {2017}, eissn = {1385-013X}, pages = {54-64}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:3273928, title = {The underthrusting Indian crust and its role in collision dynamics of the Eastern Himalaya in Bhutan: Insights from receiver function imaging}, url = {https://m2.mtmt.hu/api/publication/3273928}, author = {Singer, J and Kissling, E and Diehl, T and Hetényi, György}, doi = {10.1002/2016JB013337}, journal-iso = {J GEOPHYS RES SOLID EARTH}, journal = {JOURNAL OF GEOPHYSICAL RESEARCH: SOLID EARTH}, volume = {122}, unique-id = {3273928}, issn = {2169-9313}, abstract = {Most of the convergence rate between the Indian and Eurasian plate is assumed to be absorbed along a major basal thrust beneath the Himalaya, the Main Himalayan Thrust (MHT). Deformation along this basal thrust in combination with frontal accretion results in the formation of the upper crustal fold-thrust belt. The role of the underthrusting Indian crust and its impact on the long-term growth of the Himalaya are only poorly understood, partly due to the lack of high-resolution seismic images of the crust. To improve the imaging of lithospheric structures, we developed a 3-D migration scheme for receiver functions using seismic data from the temporary GANSSER network in Bhutan. Extending the 2-D high-frequency ray approximation and common conversion point stacking to 3-D including linear phase weighting and a quality assessment, we reveal significant along-strike differences in the lithospheric structure beneath Bhutan. In western Bhutan, the Moho geometry shows an increased dip south of the Higher Himalaya reaching almost 70 km depth thereafter, whereas in eastern Bhutan the Moho is almost subhorizontal at 50 km depth across our network. The appearance of distinct listric structures beneath the MHT indicates intracrustal deformation up to crustal imbrication down to the lower crust. We propose that these variations, in the crustal thickness and in intracrustal structures, influence the upper crustal kinematics of the Bhutan Himalayan orogeny and are primarily driven by an Indian mantle-slab northwest of Bhutan, and its absence northeast of Bhutan. ©2016. American Geophysical Union. All Rights Reserved.}, keywords = {Crustal deformation; collision; lithospheric structure; Crustal thickness; fold and thrust belt; Himalayas; imaging method; Bhután; seismic migration; Indian plate; lithosphere structure of Bhutan Himalaya; crustal deformation and accretion of underthrusting Indian plate; 3-D migration scheme for receiver functions}, year = {2017}, eissn = {2169-9356}, pages = {1152-1178}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:3167361, title = {The 2015 Gorkha earthquake: A large event illuminating the Main Himalayan Thrust fault}, url = {https://m2.mtmt.hu/api/publication/3167361}, author = {Duputel, Z and Vergne, J and Rivera, L and Wittlinger, G and Farra, V and Hetényi, György}, doi = {10.1002/2016GL068083}, journal-iso = {GEOPHYS RES LETT}, journal = {GEOPHYSICAL RESEARCH LETTERS}, volume = {43}, unique-id = {3167361}, issn = {0094-8276}, year = {2016}, eissn = {1944-8007}, pages = {2517-2525}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:3163087, title = {Joint approach combining damage and paleoseismology observations constrains the 1714 A.D. Bhutan earthquake at magnitude 8 ± 0.5}, url = {https://m2.mtmt.hu/api/publication/3163087}, author = {Hetényi, György and Le Roux-Mallouf, R and Berthet, T and Cattin, R and Cauzzi, C and Phuntsho, K and Grolimund, R}, doi = {10.1002/2016GL071033}, journal-iso = {GEOPHYS RES LETT}, journal = {GEOPHYSICAL RESEARCH LETTERS}, volume = {43}, unique-id = {3163087}, issn = {0094-8276}, abstract = {The region of Bhutan is thought to be the only segment of the Himalayas not having experienced a major earthquake over the past half millennium. A proposed explanation for this apparent seismic gap is partial accommodation of the India-Asia convergence further south across the Shillong Plateau, yet the seismic behavior of the Himalayan megathrust in Bhutan is unknown. Here we present historical documents from the region reporting on an earthquake in 1714 A.D. and geological evidence of surface rupture to constrain the latest large event in this area. We compute various earthquake scenarios using empirical scaling relationships relating magnitude with intensity, source location and rupture geometry. Our results constrain the 1714 A.D. earthquake to have ruptured the megathrust in Bhutan, most likely during a M7.5–8.5 event. This finding reclassifies the apparent seismic gap to a former information gap and implies that the entire Himalayan arc has a high level of earthquake potential. ©2016. The Authors.}, keywords = {Seismology; earthquakes; Computational geometry; Geophysics; Himalayas; Himalaya; Flexible couplings; Bhután; Historical earthquakes; seismic cycle; paleoseismology; historical earthquake; damage intensity}, year = {2016}, eissn = {1944-8007}, pages = {10695-10702}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:3163088, title = {Segmentation of the Himalayas as revealed by arc-parallel gravity anomalies}, url = {https://m2.mtmt.hu/api/publication/3163088}, author = {Hetényi, György and Cattin, R and Berthet, T and Le Moigne, N and Chophel, J and Lechmann, S and Hammer, P and Drukpa, D and Sapkota, SN and Gautier, S and Thinley, K}, doi = {10.1038/srep33866}, journal-iso = {SCI REP}, journal = {SCIENTIFIC REPORTS}, volume = {6}, unique-id = {3163088}, issn = {2045-2322}, abstract = {Lateral variations along the Himalayan arc are suggested by an increasing number of studies and carry important information about the orogen's segmentation. Here we compile the hitherto most complete land gravity dataset in the region which enables the currently highest resolution plausible analysis. To study lateral variations in collisional structure we compute arc-parallel gravity anomalies (APaGA) by subtracting the average arc-perpendicular profile from our dataset; we compute likewise for topography (APaTA). We find no direct correlation between APaGA, APaTA and background seismicity, as suggested in oceanic subduction context. In the Himalayas APaTA mainly reflect relief and erosional effects, whereas APaGA reflect the deep structure of the orogen with clear lateral boundaries. Four segments are outlined and have disparate flexural geometry: NE India, Bhutan, Nepal &India until Dehradun, and NW India. The segment boundaries in the India plate are related to inherited structures, and the boundaries of the Shillong block are highlighted by seismic activity. We find that large earthquakes of the past millennium do not propagate across the segment boundaries defined by APaGA, therefore these seem to set limits for potential rupture of megathrust earthquakes. © The Author(s) 2016.}, year = {2016}, eissn = {2045-2322}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:3163095, title = {Lateral uniformity of India Plate strength over central and eastern Nepal}, url = {https://m2.mtmt.hu/api/publication/3163095}, author = {Berthet, T and Hetényi, György and Cattin, R and Sapkota, SN and Champollion, C and Kandel, T and Doerflinger, E and Drukpa, D and Lechmann, S and Bonnin, M}, doi = {10.1093/gji/ggt357}, journal-iso = {GEOPHYS J INT}, journal = {GEOPHYSICAL JOURNAL INTERNATIONAL}, volume = {195}, unique-id = {3163095}, issn = {0956-540X}, abstract = {The current understanding of the Himalayan lithosphere stems mostly from cross-sections through the range at the longitude of the Kathmandu Basin. In this paper we laterally extend the analyses of structures and rheology along the Nepal Himalayas between the Pokhara valley and the Arun river.We take advantage of available information and a new data set including gravity measurements and a receiver function profile. It appears that the geometry of theMoho inferred from seismological profiles and long-wavelength gravity anomalies does not exhibit major East-West variations within the 350-km-wide study area. Using thermomechanical modelling, we show that the northward deepening of the Moho observed along profiles perpendicular to the main thrust faults can be interpreted simply as the bending of a strong India Plate. This result suggests a gradual mechanical decoupling between the crust and the mantle, leading to a northward decrease of the effective elastic thickness of the Indian lithosphere from ~75 km to ~25 km beneath the Ganga Basin and the Tibetan Plateau, respectively. Our results also confirm(partially) eclogitized lower Indian crust beneath southern Tibet. At shorter wavelengths, the observed gravity profiles exhibit some small lateral variations that can be interpreted in terms of east-west variations of the thickness of subsurface geological structures such as the Ganga Basin and the Tethyan Sedimentary Sequence. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.}, keywords = {rheology; CHINA; elasticity; Structural geology; lithosphere; faulting; Plates (structural components); Moho; Crustal structure; Earth structure; Himalayas; Thermomechanical treatment; Nepal; Xizang; gravity anomaly; Pokhara Valley; Kathmandu; Bagmati; Arun River; Indian plate; Rheology: crust and lithospheres; Rheology: crust and lithosphere; Lithospheric flexure; Dynamics: gravity and tectonics; Continental margins: convergent; Gravity anomalies and Earth structures; Gravity anomalies and Earth structure}, year = {2013}, eissn = {1365-246X}, pages = {1481-1493}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:3163096, title = {Flexure of the India plate underneath the Bhutan Himalaya}, url = {https://m2.mtmt.hu/api/publication/3163096}, author = {Hammer, P and Berthet, T and Hetényi, György and Cattin, R and Drukpa, D and Chophel, J and Lechmann, S and Moigne, NL and Champollion, C and Doerflinger, E}, doi = {10.1002/grl.50793}, journal-iso = {GEOPHYS RES LETT}, journal = {GEOPHYSICAL RESEARCH LETTERS}, volume = {40}, unique-id = {3163096}, issn = {0094-8276}, abstract = {We investigate flexural geometry and rheology of the India plate beneath the eastern Himalaya from a new gravity data set acquired in Bhutan. Compared to the well-studied Nepal Himalaya, the obtained Bouguer anomaly profiles across the range show shorter wavelength flexure of the lithosphere with a narrower and shallower foreland basin. This new data set and seismic Moho constraints are interpreted together in terms of lithospheric flexure using a 2-D thermomechanical model. Our results suggest that the strongest layer of the continental lithosphere beneath Bhutan is the upper mantle, as it is beneath Nepal. The observed west-to-east decrease in flexural wavelength is associated with weakening mantle rheology. The simulations show that this decrease can be related to ductile mantle behavior: either hydrated wet dunite or dry and hot olivine rheology. Both models display decoupled lithospheric layers leading to an eastward decrease of flexural rigidity from ∼1024 to ∼5·1022 N m in Nepal and Bhutan, respectively. Key Points Flexure and rheology of the India Plate in the Eastern Himalayas is investigated New gravity dataset constrains comprehensive 2D thermo-mechanical modeling Flexural rigidity decreases both across and along (W to E) the range. © 2013. American Geophysical Union. All Rights Reserved.}, keywords = {rheology; elasticity; gravity; GEOMETRY; Silicate minerals; orogeny; continental lithosphere; data set; lithosphere; Rigidity; Lithology; Gravitation; foreland basin; Gravity field; Moho; dunite; Himalayas; Bouguer anomaly; plate motion; Nepal; flexure; Thermomechanical model; Bhután; Flexural rigidities; effective elastic thickness; eastern Himalayas; Indian plate; Lithospheric flexure}, year = {2013}, eissn = {1944-8007}, pages = {4225-4230}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:1280307, title = {Underplating in the Himalaya-Tibet Collision Zone Revealed by the Hi-CLIMB Experiment}, url = {https://m2.mtmt.hu/api/publication/1280307}, author = {Nabelek, J and Hetényi, György and Vergne, J and Sapkota, S and Kafle, B and Jiang, M and Su, HP and Chen, J and Huang, BS}, doi = {10.1126/science.1167719}, journal-iso = {SCIENCE}, journal = {SCIENCE}, volume = {325}, unique-id = {1280307}, issn = {0036-8075}, abstract = {We studied the formation of the Himalayan mountain range and the Tibetan Plateau by investigating their lithospheric structure. Using an 800-kilometer-long, densely spaced seismic array, we have constructed an image of the crust and upper mantle beneath the Himalayas and the southern Tibetan Plateau. The image reveals in a continuous fashion the Main Himalayan thrust fault as it extends from a shallow depth under Nepal to the mid-crust under southern Tibet. Indian crust can be traced to 31 degrees N. The crust/mantle interface beneath Tibet is anisotropic, indicating shearing during its formation. The dipping mantle fabric suggests that the Indian mantle is subducting in a diffuse fashion along several evolving subparallel structures.}, year = {2009}, eissn = {1095-9203}, pages = {1371-1374}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} } @article{MTMT:1166017, title = {The effective elastic thickness of the India Plate from receiver function imaging, gravity anomalies and thermomechanical modelling}, url = {https://m2.mtmt.hu/api/publication/1166017}, author = {Hetényi, György and Cattin, R and Vergne, J and Nabelek, JL}, doi = {10.1111/j.1365-246X.2006.03198.x}, journal-iso = {GEOPHYS J INT}, journal = {GEOPHYSICAL JOURNAL INTERNATIONAL}, volume = {167}, unique-id = {1166017}, issn = {0956-540X}, abstract = {The range and the meaning of the effective elastic thickness (EET) in continental areas have been subject to controversy over the last two decades. Here we take advantage of the new data set from the Hi-CLIMB seismological experiment to re-estimate the EET of the India Plate along a south-north profile extending from the Ganges basin to central Tibet. Receiver functions give a high-resolution image of the base of the foreland basin at similar to 5 km depth and constrain the crustal thickness, which increases northwards from similar to 35 km beneath the indo-gangetic plain to similar to 70 km in southern Tibet. Together with available data sets including seismic profiles, seismological images from both INDEPTH and HIMNT experiments, deep well measurements and Bouguer anomaly profiles, we interpret this new image with 2-D thermomechanical modelling solutions, using different type of crustal and mantle rheologies. We find that (1) the EET of the India Plate decreases northwards from 60-80 to 20-30 km as it is flexed down beneath Himalaya and Tibet, due to thermal and flexural weakening; (2) the only resistant layer of the India Plate beneath southern Tibet is the upper mantle, which serves as a support for the topographic load and (3) the most abrupt drop in the EET, located around 200 km south of the MFT, is associated with a gradual decoupling between the crust and the mantle. We show that our geometrical constraints do not allow to determine if the upper and lower crust are coupled or not. Our results clearly reveal that a rheology with a weak mantle is unable to explain the geometry of the lithosphere in this region, and they are in favour of a rheology in which the mantle is strong.}, year = {2006}, eissn = {1365-246X}, pages = {1106-1118}, orcid-numbers = {Hetényi, György/0000-0001-9036-4761} }