seismotectonic model of the kangra chamba sector of northwest himalaya constraints from joint hypocenter determination and focal mechanism the existing seismological network in the kangra chamba sector has been upgraded with 12 three component digital seismometers to obtain new insight on the nature and sources of continued clustered seismicity in this part of northwest himalaya a combination of travel time distance plots and travel time inversion of p and s phases have been used to derive a 1d velocity model for the region the mini mum 1d velocity model divides the average 44 km thick crust into four layers the top 10 km thick layer represents the metamorphosed sediments of the chamba nappe that dominates the surface geology of the study area suggestion of a thin low velocity layer at 15 km depth possibly marks the detachment zone separating the downgoing indian plate from the overriding wedge the improved locations of epicenters show close clustering of seismic events immediately northeast of the epicenter of the 1905 kangra earthquake while away from this zone the seismicity in the chamba sector has more even distribution in the later sector space depth distribution of hypocenters suggests that strain resulting from the ongoing collision of the indian plate with asia is being consumed by reverse fault movement on the chamba thrust the clustered seismicity in the kangra sector has three distinct source regions and mechanisms 1 southward displacement of the thick chamba nappe sheet over the panjal imbricate zone along the panjal thrust accounts for the seismicity at shallow depths of less than 7 km 2 the nucleation of strains where the northeast dipping main boundary thrust mbt merges with the detachment plane produces focused seismicity near this junc tion and 3 the seismicity in a small pocket below the plane of detachment appears to be a consequence of stresses generated at the base of the northeast dipping detachment plane by the transverse structure

modeling of 2011 indonepal earthquake and scenario earthquakes in the kumaon region and comparative attenuation study using pga distribution with the garhwal region kumaon and garhwal regions are the chief terrains of uttarakhand himalaya the present article simulates the strong ground motion of the 2011 indonepal earthquake in the kumaon region using modified semi empirical technique mset acceleration records at ten stations in the near field region have been simulated which validates well with actual records and therefore confirms the reliability of mset in addition mset has been used to simulate strong motion records of future scenario earthquakes mw 7 0 and mw 8 0 in kumaon region by assuming the earthquake location same as that of 2011 indonepal earthquake isoacceleration maps are also provided which reveals more than 400 gal value of pga at epicentral distances less than 25 kms for an earthquake of magnitude 8 0 the comparison of isoacceleration map of future scenario earthquake mw 7 0 in kumaon region has been done with isoacceleration map of 1991 uttarkashi earthquake mw 6 8 in garhwal region which suggests distinct attenuation characteristics of these two regions

role of static stress transfer in earthquake occurrence in the himalaya abstract coulomb failure hypothesis suggests that earthquake interaction can lead to earthquake sequences and clustering this implies that the phenomenon should be considered a fundamental feature in any description of seismicity and evaluation of the seismic hazard and risk of a region we translate this idea to the himalaya and investigate how significantly the past earthquakes of the region may have influenced the present day seismicity and seismic hazard potential along its different segments for this we estimate separately the change in coulomb failure stress at the source of the most recent moderate magnitude earthquake along the kumaon garhwal segment the march 29 1999 chamoli earthquake due to two possible major sources these are i the process of subduction of the indian plate beneath the himalaya and ii some selected preceding moderate and small earthquakes in and around the region during their post seismic phase our results indicate that the change due to the former source completely overshadows that due to the latter the implication of our calculations is that the plate subduction processes in the himalaya i actively promote large moderate and small earthquake activity and ii also indirectly influence the regional seismicity through the occurrence of the past earthquakes

great earthquakes seismicity gaps and potential for earthquake disaster along the himalaya plate boundary abstract analysis of the space time patterns of seismicity in the himalaya plate boundary has established the existence of three seismic gaps 1 1 the kashmir gap lying west of the 1905 kangra earthquake 2 2 the central gap situated between the 1905 kangra and the 1934 bihar earthquakes 3 3 the assam gap between the 1897 and 1950 assam earthquakes this study has shown that the above great earthquakes were preceded as well as followed by long periods 19 years of decreased levels of seismic activity in the epicentral regions remarkable decrease in the seismicity following the year 1970 has been observed in the western half of the central gap as well as in the assam gap local seismic investigation in the assam gap confirms this feature and the seismicity suggests the existence there of an asperity the local seismic investigations in garhwal himalaya have shown that the small earthquakes are confined to the upper 6 8 km of the crust and may have strike slip motions these earthquakes occur in a region where teleseismically recorded events were few

the seismic hazard at tehri dam abstract the proposed 265 m high tehri dam in india would lie in one of the most hazardous areas in the world with respect to earthquakes a magnitude 8 or greater earthquake may be expected under the dam due to the unique tectonic setting and lack of detailed studies little is known about the expected ground in motion but indirect evidence suggests acceleration of over l g can be expected in these circumstances the dam design should be subject to the most rigorous dynamic analysis

dinosaur biostratigraphy of the edmonton group upper cretaceous alberta canada evidence for climate influence a high resolution biostratigraphic analysis of 287 dinosaurian macrofossils and 138 bonebeds in the edmonton group upper cretaceous of southern alberta provides evidence for at least three dinosa

estimation of the source parameters of the himalaya earthquake of october 19 1991 average effective shear wave attenuation parameter and local site effects from accelerograms abstract a simple and rapid methodology based on band limited strong motion data to obtain estimates of double couple fault plane solution average effective shear wave attenuation parameter qseff and locate and analyze sub events of the earthquake process has been presented this method will be particularly efficient in the study of smaller earthquakes that may have been recorded locally at a small number of seismological or strong motion observatories the method has been applied to investigate the moderate magnitude uttarkashi earthquake of october 19 1991 that occurred in the central seismic gap of himalaya and was recorded locally on a strong motion array the spectra of the high energy packets observed in the sh waves as approximated by the transverse components of accelerograms is modeled in terms of brune omega square model thereby we estimate parameters of the earthquake comprising of the fault plane solution strike 315 dip 19 rake 55 seismic moment 1 7 1026 dyne cm stress drop 53 bar fault slip 186 cm source duration 8 2 s and moment magnitude 6 7 which are found to be consistent with the corresponding values reported in published studies the average value of qseff in the region is estimated to be 731 264 suggesting a sufficiently cool thermal regime thus brittle behavior of crustal rocks with capacity for supporting earthquakes is expected to be a dominant process in the region the effect of site amplifications on peak ground acceleration pga has been investigated using a comparison of observed pga with a representative regression for the region furthermore two distinct phases of energy releases corresponding to two sub events of the earthquake have been identified on the sh wave records the sub events which represent asperities in the fault process are separated in time by about 6 s and 20 km in space the fault plane solution seismic moment and stress drop of these asperities have also been obtained

a tool for obtaining oriented samples of weakly to moderately indurated sedimentary rocks for paleomagnetic measurements abstract the tool is designed to take 1 inch 2 5 cm diameter cores up to 2 inches 5 cm in length in sedimentary rocks of moderate induration that cannot normally be sampled by traditional methods a stainless steel core barrel with internal scriber is hammered vertically into the rock and twisted out the core barrel is attached to an extruder which also holds a plastic bottle the core is screwed out of the core barrel directly into the bottle of the same internal diameter the vial is later cut to an acceptable length for the magnetometer and sealed with a plastic cap inasmuch as the sample is never removed from the plastic bottle fractured and bentonitic rocks which cannot be sampled by means of hand blocks or by diamond drilling can be magnetically measured

ammonite correlation of the uppermost campanian of western europe the u s gulf coast atlantic seaboard and western interior and the numerical age of the base of the maastrichtian

transatlantic correlations in the campanian maastrichtian stages by eustatic changes of sea level abstract there is good evidence that high sea levels peaked simultaneously during the late albian to turonian in the usa and northwest europe therefore it is to be expected that the principal peaks during the campanian maastrichtian now well dated in northwest europe should be detectable in the usa of the four main peaks in europe no 3 low in the zone of belemnitella langei is the most prominent and can be recognized with confidence in the western interior new jersey alabama mississippi and probably in texas the other peaks can be identified with various degrees of confidence but the sea did not persist long enough in the western interior for the last peak early in the late maastrichtian to be developed there the results change the generally assumed position of the campanian maastrichtian boundary on the foraminiferal scale the base of the maastrichtian on the belemnite scale is a considerable distance above the top of the zone of globotruncanita calcarata possibly as high as the base of the zone of gansserina gansseri in north temperate regions on the ammonite scale in the western interior of the usa the boundary is probably at the base of the zone of baculites baculus at 70 7 ma but could be at the base of the zone of b eliasi

brief reversed polarity interval during the cretaceous normal polarity superchron a striking feature of the geomagnetic time scale is the 34 m y period of normal polarity field bias known as the cretaceous normal polarity superchron new paleomagnetic data from three deep sea drilling project cores sites 317a 402a and 463 indicate that a brief interval of reversed polarity occurred during the superchron this reversed polarity interval may help refine past motions of the pacific plate and aid resolution of the statistical structure of the geomagnetic reversal chronology

the northernmost occurrence of prognathodon squamata mosasauridae from the western interior seaway of north america the marine reptile prognathodon squamata mosasauridae a mosasaurine mosasaur exhibiting a characteristically robust skull and dentition lived during the last two ages of the late cretaceous fossilized remains of animals assigned to this genus are so far known from north america europe africa and new zealand indicating their wide geographic ranges and presumed ecological and evolutionary success assignable to prognathodon a newly discovered partial marginal tooth from dorothy alberta canada 51 15 48 n extends the geographic range of the genus by 190 km northward in the northern hemisphere coupled with the new zealand record of this mosasaur the new discovery indicates that prognathodon likely ranged anywhere from 60 n to 60 s paleolatitude and these reptiles may even have been occasional inhabitants of the polar regions

a study of source parameters site amplification functions and average effective shear wave quality factor qseff from analysis of accelerograms of the 1999 chamoli earthquake himalaya the accelerograms of the 1999 chamoli earthquake and nine of its aftershocks which occurred in uttaranchal himalaya have been analyzed to investigate their source parameters the site amplification functions and the average effective shear wave quality factor qseff in the region the fault plane solution of the main shock is obtained using the spectral amplitudes of sh waves approximated by transverse components of accelerograms of the high energy packets observed in the accelerograms of the main shock it is found to be comparable with the reported solutions in other studies similarly the other source parameters viz seismic moment 5 03 1 7 1025 dyne cm stress drop 65 bars source duration 5 2 s and moment magnitude 6 4 estimated for the main shock are consistent with the values obtained in other studies the stress drops estimated for the aftershocks vary from 23 bars to 153 bars and the seismic moment from 1 4 1023 dyne cm to 2 9 1023 dyne cm the average estimated values of the effective shear wave quality factor qseff vary from 655 359 in the uttaranchal sector of himalaya and 1475 130 in the delhi region in general the qseff value increases with an increase in the epicentral distance reflecting the penetration of the waves into deeper layers of the crust as the epicentral distance of the observation point increases these values of qseff indicate that in general the curst is at low temperatures that will promote brittle behavior and conditions for episodic failure as compared to creep under the accumulated strains from plate collision at the himalaya plate boundary the site amplification characteristics at sites have been identified from the frequency bands of significant amplification observed in the spectral ratios of the horizontal to the vertical component records the decay of peak ground acceleration pga values with distance has been investigated using the empirical regression curves vis a vis the site amplification factors

fluvial sequence stratigraphy the wapiti formation west central alberta canada abstract outcrop exposures and high resolution subcrop data allow the description and mapping of four stratigraphic discontinuities in the fully nonmarine strata of the campanian maastrichtian wapiti formation western interior foreland basin alberta canada this framework defines four unconformity bounded depositional sequences a d based on sequence stratigraphic methodology well log patterns and facies analysis in ascending order sequence a records the transition from the underlying marine facies of the puskwaskau formation into the wapiti fluvial facies and consists of strongly progradational and aggradational stacking patterns sequences b and c show a similar pattern of basal amalgamated channel fill deposits that grade upwards into floodplain dominated strata finally sequence d is dominated by channelized sediments and extensive overbank facies an aggradational stacking pattern suggests deposition under high accommodation conditions maximum flooding surfaces are interpreted within fine grained deposits in the upper portions of sequences c and d they are tied to regionally extensive coals that accumulated more than 250 km away from the coeval shoreline this study provides new evidence that major coal seams may represent the extension of marine maximum flooding surfaces into the downstream controlled fluvial realm furthermore the new stratigraphic framework of subaerial unconformities and maximum flooding surfaces provides the means of subdividing the previously undifferentiated fully nonmarine wapiti formation into depositional sequences and component systems tracts

geological setting of vertebrate microfossil localities across the cretaceous paleogene boundary in southwestern saskatchewan canada the frenchman and ravenscrag formations of southwestern saskatchewan canada record an apparently continuous sequence of nonmarine clastic sediments across the cretaceous paleogene k pg boundary extensive exposures of these fossil rich sediments occur in the frenchman river valley near the towns of ravenscrag eastend and shaunavon and have been a focus of study since the 1970s despite this long history of investigation a comprehensive account of the geographic and stratigraphic positions of many of the significant fossil localities has yet to be published given this state of affairs the goals of this paper are to i document the geographic locations stratigraphic positions and lithologies of 11 key vertebrate microfossil localities including several new localities that have been recently discovered and ii provide an update on the status of these fossil localities the majority of which have not been sampled in the last 20 years four fossil localities are known from the lower paleocene

high precision u pb ca id tims dating and chronostratigraphy of the dinosaur rich horseshoe canyon formation upper cretaceous campanian maastrichtian red deer river valley alberta canada the non marine horseshoe canyon formation hcfm southern alberta yields taxonomically diverse late campanian to middle maastrichtian dinosaur assemblages that play a central role in documenting

estimation of source parameters and scaling relations for moderate size earthquakes in north west himalaya abstract the scaling relation and self similarity of earthquake process have been investigated by estimating the source parameters of 34 moderate size earthquakes m b 3 4 5 8 occurred in the nw himalaya the spectral analysis of body waves of 217 accelerograms recorded at 48 sites have been carried out using in the present analysis the brune s 2 model has been adopted for this purpose the average ratio of the p wave corner frequency fc p to the s wave corner frequency fc s has been found to be 1 39 with fc p fc s for 90 of the events analyzed here this implies the shift in the corner frequency in agreement with many other similar studies done for different regions the static stress drop values for all the events analyzed here lie in the range 10 100 bars average stress drop value of the order of 43 19 bars for the region this suggests the likely estimate of the dynamic stress drop which is 2 3 times the static stress drop is in the range of about 80 120 bars this suggests the relatively high seismic hazard in the nw himalaya as high frequency strong ground motions are governed by the stress drop the estimated values of stress drop do not show significant variation with seismic moment for the range 5 10 14 2 10 17 n m this observation along with the cube root scaling of corner frequencies suggests the self similarity of the moderate size earthquakes in the region the scaling relation between seismic moment and corner frequency m o f c 3 3 47 10 16 n m s 3 estimated in the present study can be utilized to estimate the source dimension given the seismic moment of the earthquake for the hazard assessment the present study puts the constrains on the important parameters stress drop and source dimension required for the synthesis of strong ground motion from the future expected earthquakes in the region therefore the present study is useful for the seismic hazard and risk related studies for nw himalaya

upper crustal stress and seismotectonics of the garhwal himalaya using small to moderate earthquakes implications to the local structures and free fluids abstract the work presents new focal mechanism data of small to moderate 3 0 ml 5 0 upper crustal earthquakes for the garhwal himalaya from a local seismic network installed in july 2007 majority of the epicenters of these earthquakes are located close to the main central thrust mct zone we retrieved moment tensor mt solutions of 26 earthquakes by waveform inversion the mt results and 11 small to moderate earthquakes from the published records are used for stress inversions the mt solutions reveal dominatingly thrust mechanisms with few strike slip earthquakes near chamoli the seismic cross sections illustrate that these earthquakes are located around the mid crustal ramp mcr in the detachment the optimally oriented faults from stress inversions suggest that the seismogenic fault in this region is similar to a fault plane having dip angle between 12 and 25 degrees which is compatible with the dip angle of the mcr 16 in this region p axes and the maximum horizontal compressive stress are ne sw oriented the direction of the relative motion of indian plate with respect to the eurasian plate the friction coefficient estimated from stress inversions show that the chamoli region having low friction in comparison to the overall values the free fluids trapped beneath the detachment are penetrating into the local faults hence decreasing the frictional strength and altering the prevailing stress conditions of the surroundings the present study reveals that the mcr structure is seismogenically active and producing the small moderate earthquakes in the region while the mct is probably dormant at present

a new ceratopsid dinosaur ornithischia from the uppermost horseshoe canyon formation upper maastrichtian alberta canada a skeleton of a new ceratopsid dinosaur eotriceratops xerinsularis gen et sp nov is described in this paper it is the first associated vertebrate skeleton found within the upper 20 m of the horseshoe canyon formation eotriceratops xerinsularis is a large chasmosaurine that differs from other chasmosaurines in a unique set of features in the premaxilla nasal horn core squamosal frill and epijugal the most striking of those features includes an extremely tall non recessed narial process of the premaxilla the presence of greatly elongate spindle shaped epoccipitals on the squamosal frill a deep well demarcated fossa on the anteroventral surface of the squamosal frill a sharply conical epijugal with a pronounced proximoposterior process and separate fossa like facets for the jugal and quadratojugal and the presence of an obliquely extending vascular trace meeting a transverse vascular trace ventrally on the anterior surface of the nasal horn core our phylogenetic analysis suggests that e x

seismicity patterns in the himalayan plate boundary and identification of the areas of high seismic potential abstract space time distribution of earthquakes along the himalayan plate boundary has been investigated with a view to discerning fluctuations in seismicity rates associated with great earthquakes the possibilities of epicentre migration and gaps in seismic activity data from 1800 to 1976 were considered this study shows that all great earthquakes m 8 0 were preceded by seismically quiescent periods of at least 19 years furthermore earthquake quiescence has also been recognised to follow the great earthquakes three possible trends of migration of epicentres of great earthquakes have been recognised 1 1 the first trend starts from the 1905 kangra earthquake the epicentres of subsequent earthquakes migrating eastwards along the plate boundary 2 2 the second trend of migration starts from the great nepal earthquake of 1833 associated with eastward migration 3 3 the third trend commences from the great assam earthquake of 1897 and shows a westward migration of earthquake epicentres the middle section of the himalayan convergent plate boundary 80 e to 90 e in general displays a relatively low level of seismicity as compared to the adjacent sections a remarkable decrease in seismicity following the year 1970 has been observed along a section of the himalaya which lies to the east of the rupture zone of the great 1905 kangra earthquake since 1970 the seismicity rate has also dropped in the region lying in between the rupture zones of the great assam earthquakes of 1897 and 1950 as has earlier been reported by khattri and wyss 1978 such decreases in the level of seismicity along active plate boundaries have been demonstrated to be indicative of building up of stresses leading to future great earthquakes mogi 1969 mccann et al 1979

a mesozoic time scale we present an integrated geomagnetic polarity and stratigraphic time scale for the triassic jurassic and cretaceous periods of the mesozoic era with age estimates and uncertainty limits for stage boundaries the time scale uses a suite of 324 radiomenc dates including high resolution 40 ar 39 ar age estimates this framework involves the observed ties between 1 radiometric dates biozones and stage boundaries and 2 between biozones and magnetic reversals on the seafloor and in sediments interpolation techniques include maximum likelihood estimation smoothing cubic spline fitting and magnetochronology

palaeoenvironmental and palaeoclimatic reconstruction of the upper cretaceous late campanian early maastrichtian horseshoe canyon formation alberta canada abstract pedogenic features and geochemical signatures of paleosol profiles exposed in the horseshoe canyon formation hcfm were studied to reconstruct the ancient environments and climates that prevailed at high latitude 60 n in the north american western interior during the late campanian to early maastrichtian eight pedotypes representing hydromorphic moderately drained and well drained paleosols were recognized when considered within their stratigraphic context these paleosols show that palaeoenvironmental and palaeoclimatic changes occurred either gradually between major lithological subdivisions of the hcfm or relatively rapidly within subdivisions hydromorphic paleosols predominant in the coal bearing stratigraphic interval at the base of the hcfm were gradually replaced by well drained paleosols in the overlying coal poor interval while climate remained warm and humid during this change in soil drainage conditions mean annual temperature and precipitation dropped rapidly higher in section shortly prior to the campanian maastrichtian boundary without concomitant lithological or pedological changes a brief return of poorly drained paleosols in the middle of the hcfm coincides with a regional marine transgression drumheller marine tongue well drained palaeoenvironments associated with a warm and dry climate persisted through the upper part of the hcfm until a gradual return to poorly drained conditions and to a warm humid climate occurred at the top of the formation an important decline in turtle diversity through the hcfm previously attributed to climate is shown to coincide instead with changes in soil drainage conditions where aridity landscape instability and migratory barriers possibly acted as secondary limiting factors to faunal recovery

southern limits of major earthquake ruptures along the himalaya between longitudes 75 and 90 e the ruptures responsible for major earthquakes along the himalayan convergent plate margin hcpm occur in a strikewise oriented zone of frictional failure and relative slip in a buried detachment along the upper surface of the indian shield rocks subducting under the himalaya the southern limit of the rupture zone is a geotectonic lineament whose geographic location is important in assessing risk due to earthquakes a major part of this article is taken up in arguing that the available macroseismic and instrumental evidence for the 1934 bihar nepal earthquake is consistent with the view that the rupture which caused it occurred in the detachment mostly under the lesser himalaya northward from the vicinity of the surface trace of the main boundary thrust mbt since a similar location has been inferred by others for the 1905 kangra earthquake rupture a basis arises for postulating that over more than half of the length of the hcpm between 75 and 90 e longitudes the ruptures responsible for major earthquakes lie in the detachment with their southern limits geographically similarly close to the surface trace of the mbt this includes the nearly 700 km long seismic gap between the 1905 and 1934 ruptures

spatial distribution of earthquake potential along the himalayan arc abstract to determine the spatial distribution of earthquake potential along the active himalayan arc we utilize gps measurements and earthquake data we derive horizontal velocity field and 2 d strain rates from a new set of 41 regional gps stations along with 446 published velocities we convert these strain rate tensors to geodetic moment rate build up within 24 contiguous segments and compare to the seismic moment rate release derived from a reassessed earthquake catalog of 900 years the geodetic to seismic moment rate ratio an indicator of stored strain energy varies from below unity to more than 50 in different segments the estimated geodetic moment rate ranges from 1 7 1018 nm yr to 10 2 1018 nm yr whereas the seismic moment rate ranges from 3 7 1016 nm yr to 5 1 1019 nm yr this variation between the geodetic and seismic moment rate corresponds to a moment deficit rate of 1 15 1017 nm yr to 7 97 1018 nm yr along various segments of the study region the above moment deficit rate provides an equivalent earthquake potential of magnitude 5 7 8 2 in different segments specifically the higher earthquake potential mw 8 0 corresponds to the segments in the central seismic gap and the northeast part of himalaya whereas the lower earthquake potential mw

geological and geomorphic evidences of neotectonic activity along the himalayan frontal thrust nahan salient nw himalaya india abstract in this paper we report geomorphic signatures of neotectonic activity identified from the area around nahan salient along himalayan frontal thrust hft using remote sensing and field investigations we document two newly discovered exposures of hft fault zone and active fault traces along the mountain front at khetpurali nahan salient nw himalaya india we demonstrate that hft fault zone at khetpurali is not blind instead it is exposed at the surface along with highly deformed folded strata in the hanging wall and its geometry is quite variable with the possibility of along strike segmentation the geometry of fold and various deformational features preserved in the hanging wall indicate a process of fault propagation fold this is in contrast to the previous observation of fault bent folding within the nahan salient two three levels of river terraces are preserved and truncated in the hanging wall along with the active fault scarps which are linked to uplift along hft fault zone the khetpurali anticline ka is a fault propagating fold formed due to displacement and shortening along hft which dips 30 towards north and strike wnw ese the uplift u along the ka is calculated to be 73 m and accommodated 7 3 shortening of the original length before the fault tip truncated the fold various deformational structures have been identified within the hanging wall around tip damage zone of 80 m perpendicular to hft fault zone and in the core of ka northwest of khetpurali a south facing hogback structure 100 m high is formed due to erosion of forelimb of the anticline at khetpurali tectonic control due to folding of strata and uplift of river terraces is evident as the dudhgarh river forms v shaped profile near the thrust compared to the wide floodplain before and after crossing the hft fault zone along strike segmentation of hft and associated anticlines is observed as the surface trace of hft is offset at khetpurali trilokpur and sabilpur due to the strike slip faults the study reveals that hft has been truncated by tear faults and has different subsurface geometries in study area which may have implication on seismic hazard in the nahan salient where three thrusts himalayan frrontal thrust hft nahan thrust nt and main boundary fault mbf are located at relatively shorter distance of 6 km as compared to the surrounding recesses

earthquake recurrence in nw and central himalaya abstract in this study we compare himalayan seismic moment release estimates derived from strain rate observations with those derived from large historical earthquakes and to this end we use a reassessed catalogue of historical earthquakes from western and central himalaya since the beginning of the 16th century we have computed seismic moment rates within six contiguous segments along the himalayan arc and compared these using kostrov s formula with moment rates computed from recent global strain rate estimates and regional studies while the ratios between strain based moment rate estimates and those inferred from observed seismicity vary significantly between the segments we find on the average consistently larger strain based values by about a factor of two based on seismicity from the last 515 years the moment rate ratio is however significantly reduced when shorter catalogues are used to 1 28 for the last 215 years and to 1 05 for the last 115 years which is an almost perfect match the possible inclusion of afterslip in the model would further improve the 515 year match this is indicating that a significant part of the difference possibly most of it is likely to be caused by incompleteness of the longer earthquake catalogue possibly combined with underestimated magnitudes the difference between geodetic and seismic estimates for the more complete part of the catalogue is smaller than previously reported along the western himalayan frontal thrust in fact the only region where a significant moment rate difference is found in our study is in se himachal pradesh in terms of seismic hazard it is found that the moment rate reduction of about a factor of two when going from 115 to 515 years leads to a reduction in the 475 year pga of about 26 it is also found that using 50 years of usgs seismicity data between 1963 and 2012 leads to a 40 lower hazard as compared to using moment release for the last 115 years

revisiting the 1991 uttarkashi and the 1999 chamoli india earthquakes implications of rupture mechanisms in the central himalaya abstract the central himalaya has attracted much attention due to its potential to host a great earthquake an inference based on the history of earthquakes and the geodetic slip estimates the largest and earliest historically documented earthquake in the central himalaya occurred in 1803 m 7 7 near uttarkashi on its western part much before the great event of 1934 mw 8 2 located farther to the east both of which were felt severely in the gangetic plain south of the mountain front the seismotectonic model by seeber and armbruster 1981 predicts that large great earthquakes originate on the main himalayan thrust mht and their ruptures propagate southward to the main frontal thrust mft the rupture of the april 25 2015 mw 7 8 gorkha nepal earthquake however was southeast directed with a southwest directed slip and its mw 7 3 aftershock on may 12 also showed a similar slip direction post 2015 we revisited the 1991 uttarkashi mw 6 7 and the 1999 chamoli mw 6 5 earthquakes in india both of which had originated on the mht flat but show ssw directed slips as reported in this study ruptures of both these earthquakes fell short of reaching the mft just as the historically documented 1803 earthquake but their shaking effects were felt in the southern plains these observations compel us to conclude that the varying rupture modes exhibited by the himalayan earthquakes are controlled primarily by the geometry of the flat ramp flat system

genesis and implication of soft sediment deformation structures in high energy fluvial deposits of the alaknanda valley garhwal himalaya india abstract valley fill terraces and fluvio lacustrine sediment successions were investigated for the nature and type of soft sediment deformation structures ssds in the alaknanda valley of the garhwal himalaya based on their morphologies sediment characteristics and comparison with existing data on ssds these features are classified into seismic and aseismic categories the study indicates that despite the terrain being in the seismically active domain of the central himalaya the majority of the deformation structures seem to have been generated aseismically we attribute their genesis to uneven loading slope failure and most importantly turbulent flow and sudden loading by flash floods the study suggests that a cautious approach is needed before assigning a seismic origin to deformation structures in sediments deposited in high energy fluvial systems

high resolution organic carbon isotope record across the cretaceous tertiary boundary in south central alberta implications for the post impact recovery rate of terrestrial ecosystems and use of δ13c as a boundary marker a high resolution study identified a 13 c excursion of 1 8 to 2 3 in terrestrial organic matter across the cretaceous tertiary k t boundary at two localities in the scollard formation of south central alberta one of the northernmost occurrences of the k t boundary in terrestrial settings 13 c values are at their lowest within 6 cm above the k t boundary claystone and return to pre boundary levels within 10 cm above the boundary claystone statistical analyses reveal that the k t isotopic shift in alberta is related to the nature of floral changes that occurred across the k t boundary a radiometrically dated bentonite resting on the boundary hosting nevis coal at one of the localities permits us to estimate that the terrestrial carbon cycle recovered 100 000 years after the k t boundary event a value that supports an existing hypothesis that terrestrial ecosystems recovered more rapidly than marine ecosystems the organic carbon isotope record of the entire scollard formation demonstrates that the 13 c excursion across the k t boundary did not reach anomalously low values by late maastrichtian standards in alberta furthermore the occurrence of the k t carbon isotope shift within a restricted stratigraphic interval 10 cm greatly limits the probability of its preservation in the context of terrestrial sedimentary environments these observations suggest that on their own 13 c profiles may be unreliable for locating the k t boundary and possibly other geologically instantaneous events and that they should be used in combination with other approaches e g palynology to identify the k t boundary in sections lacking the boundary claystone and iridium anomaly resume une etude de haute resolution a identifie une excursion isotopique 13 c varient entre 1 8 et 2 3 dans

seismicity in the kingdom of bhutan 1937 2003 evidence for crustal transcurrent deformation we investigate moderate sized historic to recent earthquakes in the bhutan himalaya spanning the years from 1937 to 2003 we find that few moderate sized earthquakes occurred in the region during this time period in order to better characterize the seismicity we relocate all earthquakes and estimate focal mechanisms for events for which we have adequate data we use first motion data for older events and waveform model digital seismograms for three earthquakes that occurred in 1980 m w 6 4 1995 m w 5 4 and 2003 m w 5 4 for the modern events we utilize three techniques for focal mechanism and depth determination regional full waveform time domain modeling of the two moderate m w 5 4 events and surface wave spectral method and body wave depth modeling approach for the m w 6 4 event we find that the first motion and digital data focal mechanisms are mostly strike slip with midcrustal to deep crustal depths although no recent great event has occurred along the main himalayan thrust the indian plate is undergoing significant midcrustal to deep crustal transcurrent deformation likely due to oblique convergence of the indian asian collision in this region unlike oceanic continent oblique subduction strike slip and thrust partitioning occurs throughout the crust not in distinct zones the geological and geophysical nature of the bhutan himalaya appears significantly different than other himalayan regions due to the strike slip nature of many of the events an out of sequence thrust fault and the implications of deformation in the shillong plateau

an overview on the seismic zonation and microzonation studies in india abstract the present study presents a review on the progressive development of the seismic zonation map of india both from official agencies and also from independent individual studies the zonation map have been modified and updated regularly with the occurrence of major destructive earthquakes over the years in the indian subcontinent with the addition of new data this study discusses the criteria chosen for the progressive zonation and the major earthquakes that were responsible for retrospection of the earlier published maps the seismic zonation maps of india have also been prepared by various independent workers by adopting different approaches to achieve the purpose of the zonation despite the endeavors from various sources to provide a solution for the problem of earthquake hazards in india there were many limitations on the zonation map as it gives the picture at a regional scale mostly on the bedrock level without addressing the local site conditions but nevertheless the seismic zonation map gives basic guidelines for any region to know the hazard scenario and if any city or urban population is under threat from seismic point of view further site specific seismic microzonation may be carried out in the international scenario the global seismic hazard assessment program gshap in 1999 prepared a hazard map for world in terms of peak ground acceleration pga with a 10 probability of exceedance in 50 years but it turned out to be an underestimation of the hazard parameter when compared with the observed pga to tackle the problem of seismic hazards there was a need to have a detail study on the local site conditions in terms of its geological geophysical and geotechnical properties with the advent of better instrumentation and knowledge on the mechanics of earthquakes it was possible to identify zones of hazards at a local level and this gives rise to the study of seismic microzonation seismic microzonation work has been carried out in india in some of the strategic important mega cities and industrial build up that has the potential of being damaged from future earthquakes as has been shown in the past though the microzonation map is not the final output map as it can still be updated at later stage with more input data it does provide a more realistic picture on the site specific seismic hazard

stability assessment and quantitative evaluation of h v spectral ratios for site response studies in kumaon himalaya india using ambient noise recorded by a broadband seismograph network the kumaon himalaya region in india has accumulated considerable seismic risk potential from moderate to high seismicity due to ongoing tectonic evolutionary processes to assess conditions of high seismic risk arising from local site effects at populated locations we applied the empirical horizontal to vertical h v spectral amplitude ratio method nakamura in quarterly reports of the railway technical research institute tokyo 30 25 33 1989 using ambient seismic noise recorded by a network of 32 digital broadband seismographs from june 2005 to june 2008 the data and the estimated parameters were subjected to stability tests to assess the effect of seasonal variations seasonal variations in the ambient noise data seemed to show a lesser effect on fundamental frequency estimates and a slightly greater effect on the peak h v amplitudes validation of the ambient noise results was done by complementary tests using h v ratios of local and regional earthquakes the peak corresponding to the fundamental resonance frequency is prominently present in both the ambient noise and the earthquake datasets the study locations showed distinct h v curve topologies corresponding to the effects of both velocity contrast at well defined frequencies and characteristic topographic effect around a certain frequency range the clearly indicated peaks in the h v curves possibly correspond to velocity contrasts created by weathered sediments overlying hard rock basements in rocky hills our study indicates high site responses at many populated locations near the surface trace of the seismically active main central thrust mct and other fault boundaries the fundamental resonance frequencies estimated from the site response studies at the 32 locations could be useful in preliminary site characterization ground motion prediction and seismic hazard analysis

estimation and applicability of attenuation characteristics for source parameters and scaling relations in the garhwal kumaun himalaya region india abstract source parameters of the small to moderate earthquakes are significant for understanding the dynamic rupture process the scaling relations of the earthquakes and for assessment of seismic hazard potential of a region in this study the source parameters were determined for 58 small to moderate size earthquakes 3 0 m w 5 0 occurred during 2007 2015 in the garhwal kumaun region the estimated shear wave quality factor q f values for each station at different frequencies have been applied to eliminate any bias in the determination of source parameters the q f values have been estimated by using coda wave normalization method in the frequency range 1 5 16 hz a frequency dependent s wave quality factor relation is obtained as q f 152 9 7 f 0 82 0 005 by fitting a power law frequency dependence model for the estimated values over the whole study region the spectral low frequency spectral level and corner frequency and source static stress drop seismic moment apparent stress and radiated energy parameters are obtained assuming 2 source model the displacement spectra are corrected for estimated frequency dependent attenuation site effect using spectral decay parameter kappa the frequency resolution limit was resolved by quantifying the bias in corner frequencies stress drop and radiated energy estimates due to finite bandwidth effect the data of the region shows shallow focused earthquakes with low stress drop the estimation of zuniga parameter e suggests the partial stress drop mechanism in the region the observed low stress drop and apparent stress can be explained by partial stress drop and low effective stress model presence of subsurface fluid at seismogenic depth certainly manipulates the dynamics of the region however the limited event selection may strongly bias the scaling relation even after taking as much as possible precaution in considering effects of finite bandwidth attenuation and site corrections although the scaling can be improved further with the integration of large dataset of microearthquakes and use of a stable and robust approach

faunal assemblages from the upper horseshoe canyon formation an early maastrichtian cool climate assemblage from alberta with special reference to the albertosaurus sarcophagus bonebed the faunal assemblage from the early maastrichtian portion of the horseshoe canyon formation is described on the basis of four new vertebrate microfossil localities and remains from the albertosaurus bonebed all of the localities sampled were deposited during a cool dry climate at a palaeolatitude of 58 n thus these assemblages provide insight into a northern cool climate assemblage in the early maastrichtian of western north america this fauna is characterized by the presence of taxa with more northern affinities such as holostean a champsosaurs troodon and toothed birds warm climate taxa such as crocodylians large and diverse turtles and albanerpetontids are notable in their absence the albertosaurus bonebed locality at the top of unit 4 of the horseshoe canyon formation was deposited during the initial stages of a trend to a warmer and wetter climate that is represented in unit 5 the bonebed shares many taxa with the underlying vertebrate microfossil localities however a notable diffe

mapping of shallow three dimensional variations of p wave velocity in garhwal himalaya abstract a set of short aperture seismic arrays was operated in the garhwal himalaya close to the main central thrust and recorded a large number of small local earthquakes this study pertains to the inversion of the body wave arrival time data of these earthquakes to construct a seismic velocity model for the region the analysis indicates a systematic variation in the p wave velocities of the upper crustal rocks we estimate i significantly lower seismic velocities within the middle lesser garhwal himalaya and ii higher seismic velocities in the interface zone between the middle lesser and higher garhwal himalaya seismic activity is mostly confined to a relatively narrow north east dipping zone in the upper 4 km of the crust characterized by a relatively higher p wave velocity this active seismicity represents reverse thrusting along steep north easterly dipping parallel slip surfaces within this zone forming a ramp in the crystalline formations of higher himalaya the lower velocity zone exhibits a low level of seismicity but appears to be associated with an increased landslide hazard

late pleistocene and holocene large magnitude earthquakes along himalayan frontal thrust in the central seismic gap in nw himalaya kala amb india abstract the himalayan frontal thrust hft forms the southernmost active tectonic mountain front of the himalaya to understand the ongoing tectonics further paleoseismological study has been carried out in the vicinity of the hft system along the himalayan front near kala amb india the trench excavation survey conducted across an explicit surface exposure of the hft exhibits two distinct faults considered to be associated with the reactivation of the hft where the middle siwalik rocks late miocene have repeatedly thrust over the late pleistocene and holocene sediments presence of large sized coseismically induced sand injection feature and its disposition recognized in the trench also suggest occurrence of large magnitude earthquakes in this region an uplifted and upwarped strath terrace 3 to 5 m thick alluvium resting over the 15 m high middle siwaliks abruptly truncated by the hft indicates its latest activity optically stimulated luminescence dating techniques were employed to constrain the chronology of events the long term slip rate of the abandoned terraces due to the activity of the hft is estimated to be 3 4 mm yr or greater since late holocene the paleoseismological investigations have provided unambiguous evidences of at least two large magnitude earthquakes occurred in this region where an earthquake with 12 m or larger surface displacement and magnitude 7 5 or greater hit this region in the period between 29 3 ka and 17 ka in the late pleistocene and another great earthquake recurred with 20 22 m or more surface displacement and magnitude of 7 7 or greater between 5 8 ka and 2 ka in the holocene the present study is the first time report of multiple large magnitude paleoearthquakes in the northwestern part of the frontal himalaya during late pleistocene and holocene the repeated reactivation of hft substantiates high seismic potential of the frontal himalaya and calls for more extensive study of paleoearthquakes of this vastly populous mountainous region

geochronologic and thermobarometric constraints on the evolution of the main central thrust central nepal himalaya the main central thrust mct juxtaposes the high grade greater himalayan crystallines over the lower grade lesser himalaya formation an apparent inverted metamorphic sequence characterizes the shear zone that underlies the thrust garnet bearing assemblages sampled along the marysandi river and darondi khola in the annapurna region of central nepal show striking differences in garnet zoning of mn ca mg and fe above and below the mct thermobarometry of mct footwall rocks yields apparent inverted temperature and pressure gradients of 18 c km 1 and 0 06 km mpa 1 respectively pressure temperature p t paths calculated for upper lesser himalaya samples that preserve prograde compositions show evidence of decompression during heating whereas garnets from the structurally lower sequences grew during an increase in both pressure and temperature in situ i e analyzed in thin section ion microprobe ages of monazites from rocks immediately beneath the greater himalayan crystallines yield ages from 18 to 22 ma whereas late miocene and pliocene monazite ages characterize rocks within the apparent inverted metamorphic sequence a lesser himalayan sample collected near the garnet isograd along the marysandi river transect contains 3 3 0 1 ma monazite ages p 0 72 gpa t 535 c this remarkably young age suggests that this portion of the mct shear zone accommodated a minimum of 30 km of slip over the last 3 ma i e a slip rate of 10 mm yr 1 and thus could account for nearly half of the convergence across the himalaya in this period the distribution of ages and p t histories reported here are consistent with a thermokinematic model in which the inverted metamorphic sequences underlying the mct formed by the transposition of right way up metamorphic sequences during late miocene pliocene shearing

probabilistic assessment of earthquake hazards in the north east indian peninsula and hindukush regions the himalayan region is one of the most seismic prone areas of the world the north east ne indian peninsula and the hindukush regions mark the zone of collision of the indian and eurasian plates the probability of the occurrence of great earthquakes with magnitude greater than 7 0 during a specified interval of time has been estimated on the basis of four probabilistic models namely weibull gamma lognormal and exponential for the ne indian peninsula and hindukush regions the model parameters have been estimated by the method of maximum likelihood estimates mle and the method of moments mom the cumulative probability is estimated for a period of 40 years from 1964 and is ranging between 0 881 to 0 995 by the year 1995 using all four models for the ne indian peninsula the conditional probability is also estimated and it is concluded that the ne indian peninsula would expect a great earthquake at any time in the remaining years of the present century for the hindukush region the cumulative probability has already crossed its highest value but no earthquake of magnitude greater than 7 0 has occurred after 1974 in this area it may attribute to the occurrence of frequent shocks of moderate size as seventeen earthquakes of magnitude greater than 6 0 including four greater than 6 4 have been reported until 1994 from this region

estimation of strong ground motion from a great earthquake mw 8 5 in central seismic gap region himalaya india using empirical green s function technique in the present study ground motions for a mw 8 5 scenario earthquake are estimated at 13 sites in kumaun garhwal region using the empirical green s function technique the recordings of 1991 uttarkashi earthquake of mw 6 8 at these sites are used as an element earthquake a heterogeneous source model consisting of two asperities is considered for simulating the ground motions the entire central seismic gap csg can expect acceleration in excess of 100 cm s2 with nw portion in excess of 400 cm s2 and se between 100 and 200 cm s2 the central portion can expect peak ground acceleration pga between 200 and 400 cm s2 it has been observed from simulation of strong ground motion that sites located near the rupture initiation point can expect accelerations in excess of 1g in the present analysis bhatwari and uttarkashi can expect ground accelerations in excess of 1g the estimates of the pga are compared with earlier studies in the same region using different methodologies and it was found that the results are comparable this has put constrains on the expected pgas in this region the obtained pga values can be used in identifying the vulnerable areas in the central himalaya thereby facilitating the planning design and construction of new structures and strengthening of the existing structures in the region

seismogenesis of clustered seismicity beneath the kangra chamba sector of northwest himalaya constraints from 3d local earthquake tomography abstract to investigate subsurface structure and seismogenic layers 3d velocity inversion was carried out in the source zone of 1905 kangra earthquake m8 0 in the northwestern himalaya p wave and s wave phase data of 159 earthquakes recorded by a network of 21 stations were used for this purpose inverted velocity tomograms up to a depth range of 18 km show significant variations of 14 in vp and vs and 6 in the vp vs across the major tectonic zones in the region synthesis of seismicity pattern velocity structure distinctive focal mechanisms coupled with nature of stress distribution allows mapping of three different source regions that control regional seismotectonics accumulating strains are partly consumed by sliding of chamba nappe to the southwest through reverse fault movements along chamba panjal main boundary thrusts this coupled with normal fault type displacements along chenab normal fault in the north account for low magnitude widespread seismicity in upper 8 10 km of the crust at intermediate depths from 8 to 15 km adjusting to residual compressive stresses the detachment or lower end of the mbt slips to produce thrust dominated seismicity nucleation of secondary stresses in local ne sw oriented structure interacts in complex manner with regional stresses to generate normal type earthquakes below the plane of detachment and therefore three seismic regimes at different depths produce intense seismicity in a block of 30 30 km 2 centered ne to the epicenter of kangra earthquake

modelling of active lineaments for predicting a possible earthquake scenario around dehradun garhwal himalaya india abstract the doon valley which consists of the doon gravels and siwalik rocks is surrounded by the main boundary thrust mbt in the north the main frontal thrust mft mohand thrust and bhimgoda thrust in the south the ganga tear fault in the east and the yamuna tear fault in the west lineaments identified from the aerial photographs show that a few of them trend parallel to the himalayan orogen and the others are transverse to it the effect of the neotectonic activity is clearly reflected in the doon valley implying that the doon valley is tectonically unstable today and that the possibility of earthquakes in this region cannot be ruled out the ruptures along identified active lineaments are modelled three dimensionally peak accelerations are obtained by using a methodology based on the semi empirical method of irikura which was used by midorikawa the efficacy of this modelling technique for the himalayan region is established by simulating peak ground accelerations for the uttarkashi earthquake of 20 october 1991 and comparing it with recorded one a seismic study of the region shows that it is prone to moderate as well as great earthquakes the technique of midorikawa has been applied for the preparation of zonation maps in this seismically active region two different zonation maps showing respectively the effects of moderate as well as great earthquakes in this region are presented in this paper the zonation map for moderate earthquakes shows that the region can experience peak ground accelerations around 310 cm s2 this value is close to the peak ground acceleration of 304 cm s2 recorded for the uttarkashi earthquake ms 7 1 at uttarkashi station which is about 60 km north of dehradun the prepared map shows that among all identified active lineaments rupture along four lineaments can cause major damage in the region among these four three lineaments are transverse to the major tectonic zones viz the mft and mbt in the region and one extends along the mft lying south of dehradun the zonation map for great earthquakes m 8 has been prepared by modelling a rupture in the central gap region of the himalaya seven different possibilities of rupture nucleation within the rupture plane are modelled and a zonation map containing three different zones is prepared the prepared zonation map for this worst possible scenario shows that cities like tehri uttarkashi srinagar deoprayag pauri and dehradun fall within zone 1 and can experience ground accelerations bigger than 600 cm s2 the region like hardwar and rishikesh fall within zone 2 and can experience ground accelerations around 300 cm s2 the zonation map shows that tehri can experience accelerations up to 0 84g and this value is comparable with that obtained by other researchers this study confirms that for very long periods the destruction in the region will be dominantly affected by ruptures having longer lengths and least effected by shorter ruptures therefore special consideration about the longer ruptures should be taken while considering effect of earthquake hazards in this region

tectonic control of high frequency depositional sequences with durations shorter than milankovitch cyclicity an example from the pleistocene paleo tokyo bay japan forcing mechanisms of high frequency depositional sequences in late cenozoic successions have commonly been interpreted in terms of glacio eustasy in contrast we demonstrate here the effects of local tectonics in the development of high frequency depositional sequences in a middle and upper pleistocene succession examples are from shallow marine and coastal deposits developed in the paleo tokyo bay japan and are based on a detailed chronostratigraphic framework constructed from dated volcanic ash beds within highstand successions of the glacio eustatic sequences we have mapped locally developed high frequency depositional sequences within areas that have undergone anticlinal uplift these high frequency depositional sequences pass laterally into parasequences overlying marine flooding surfaces in adjacent synclinal areas spatial variation in such stratigraphic features indicates local tectonic movements in the paleo tokyo bay area during rises and highstands of glacio eustatic sea level cycles the duration of such high frequency depositional sequences is estimated as 10 k y shorter than milankovitch cyclicity the present example indicates that local basin tectonics can be an important forcing mechanism of high frequency depositional sequences in pleistocene successions in an active margin basin

relevance of seismicity in kumaun garhwal himalaya in context of recent 25th april 2015 m w 7 8 nepal earthquake abstract due to the continuous movement of underthrusting indian plate beneath the eurasian plate the strain energy accumulates which is released substantially in the form of great earthquakes it is yet to be released in the unruptured zone which lies between the two great earthquakes viz 1934 bihar nepal earthquake and 1905 kangra earthquake this zone has been termed as the central seismic gap csg the occurrence of previous great earthquakes and recent nepal earthquakes gives a clue to the probable location of future great earthquake on the basis of analysis of seismicity in the locked portion and the stress drop analysis the csg has been redefined and location of probable zone of future great earthquake has been demarcated

aftershocks of the march 1999 chamoli earthquake and seismotectonic structure of the garhwal himalaya the aftershocks of the chamoli earthquake m b 6 3 of 28 march 1999 are analyzed to understand the seismotectonic structure of the garhwal himalaya the permanent as well as temporary microearthquake network data are used the mainshock occurred on the basement thrust by thrust faulting the aftershocks on the other hand are triggered at the seismogenic faults to the south of the main central thrust mct by thrust faulting as well as by strike slip faulting and all the events occurred above the plane of detachment basement thrust the mct is not the seismogenic fault

a review of nonmarine turtles from the late cretaceous of alberta the late cretaceous of alberta preserves one of the most complete records of fossil turtles within a single geographic area in north america the cenomanian dunvegan formation contains the earliest record of the family trionychidae in north america the santonian milk river formation contains a minimum of ten taxa with adocus a small trionychid and a member of the solemydidae being the most abundant diversity remains high in the mid campanian judith river group the solemyidid last occurs in the basal beds of the judith river group a member of the macrobaenidae first occurs in the dinosaur park formation the uppermost formation in the judith river group turtles diversity is low in the late campanian lower horseshoe canyon formation and they are absent in the early maastrichtian upper horseshoe canyon formation diversity increases in the late maastrichtian scollard formation although it is much less than in the contemporaneous hell creek formation of montana two of the taxa present in the scollar

upper cretaceous palynostratigraphy of the dry island areathis article is one of a series of papers published in this special issue on the theme albertosaurus the overall palynology of the upper horseshoe canyon formation to lower scollard formation within the edmonton group is reviewed providing new insights into biostratigraphic relationships for the interval including the recognition of unconformities in the stratigraphic package the palynomorph recovery from the horseshoe canyon formation and overlying units documents a number of significant events that allow the subdivision of the section the albertosaurus bonebed occurs within the lower maastrichtian portion of the edmonton group the bonebed is situated just below the base of the scollardia trapaformis palynomorph zone an important marker assemblage that has been documented from areas of the yukon northwest territories alberta and saskatchewan this indicates that the bonebed lies at the top of the mancicorpus vancampoi zone the transition between the zones is marked by a colour change in the sediments the appearance of coals and organic rich sediments above the transition a decrease in numbers

ammonoid habitats and habits in the western interior seaway a case study from the upper cretaceous bearpaw formation of southern alberta canada abstract multidisciplinary research on the habitats and life habits of ammonoids of the upper cretaceous bearpaw formation is based on hydrostatics and hydrodynamic aspects of shell shapes occurrence in lithofacies evidence of predation and stable isotopic data the large and well streamlined oxyconic placenticeras with large chitinous anaptychus had the weakest shells known and suffered mosasaur tooth perforations at minimal ambient pressure anomalously light 18 o signatures preserved in their aragonitic shells suggest that they grew in brachyhaline water juveniles and some adults of orthoconic baculites had a vertical life orientation and primarily resided in the lower to middle levels of the water column flourishing during oxygenation events some adults however may have changed to a mainly horizontal swimming habit in mid water attitudinal change is indicated by relative shortening of the body chamber during late ontogeny neutral buoyancy at maturity could have been achieved only with a partially liquid filled phragmocone implying the exceptional use of cameral liquid as an apical counterweight juvenile scaphitids were planktic or sluggishly nektic as implied by sphaeroconic and discoconic immature whorls respectively the adults had different habits as indicated by their strongly modified body chambers which gave high stability suited to vertical swimming adult hoploscaphites and most jeletzkytes with open hooked scaphitoconic body chambers were demersal and lived close to the sea floor during oxygenation events whereas adult rhaeboceras with an elliptical contracted body chamber elliptosphaerocone lived in mid water

homogenization of earthquake catalog for northeast india and adjoining region a catalog for northeast india and the adjoining region for the period 1897 2009 with 4 497 earthquakes events is compiled for homogenization to moment magnitude m w gcmt in the magnitude range 3 8 7 relations for conversion of m b and m s magnitudes to m w gcmt are derived using three different methods namely linear standard regression inverted standard regression isr and orthogonal standard regression osr for different magnitude ranges based on events data for the catalog period 1976 2006 the osr relations for m s to m w gcmt conversion derived in this paper have significantly lower errors in regression parameters compared to the relations reported in other studies since the number of events with magnitude 7 for this region is scanty we therefore considered whole india region to obtain the regression relationships between m w gcmt and m s isc a relationship between m w gcmt and m w neic is also obtained based on 17 events for the range 5 2 magnitude 6 6 a unified homogeneous catalog prepared using the conversion relations derived in this paper can serve as a reference catalog for seismic hazard assessment studies in northeast india and the adjoining region

a new calibration point for the late cretaceous time scale the 40 ar 39 ar isotopic age of the c33r c33n geomagnetic reversal from the judith river formation upper creataceous elk basin wyoming usa we present a new calibration point for the latest cretaceous time scale an interval that at present contains no well dated polarity reversals the magnetostratigraphy of campanian aged sediments in the northern bighorn basin of wyoming documents a geomagnetic reversal in the upper part of the judith river formation that occurs in direct association with ash fall layers dated by the 40 ar 39 ar method extrapolation based on three new 40 ar 39 ar laser fusion dates from sanidines extracted from the ash fall layers dates the reversal at 79 34 ma thus the geomagnetic reversal in the judith river formation can be confidently correlated to the c33r c33n boundary of the geomagnetic reversal time scale this age estimate is in good agreement with recent time scales that date this polarity interval by interpolation between few and widely spaced calibration points the judith river formation is nonmarine and cannot be correlated regionally by traditional ammonite biostratigraphic methods this st

characteristic ground motions of the 25th april 2015 nepal earthquake mw 7 9 and its implications for the structural design codes for the border areas of india to nepal abstract the 25th april 2015 nepal earthquake was found associated with a series of aftershocks and the mainshock rupture propagated predominantly towards se direction where a major aftershock mw 7 3 rocked on 12th may 2015 to the east of the mainshock that enhanced the rate of occurrence of aftershocks in the affected region we conducted a rigorous analysis of strong motion data to understand the characteristics of ground motion and their bearing on the structural design codes responsible for the damage to the structures in the border area of india to nepal the effect of ground geology on the acceleration response spectra are also evaluated using main shock and its associated strong earthquakes all the sites used in the present analysis are located on alluvium deposits showing a predominant period of 0 242 sec for horizontal components and at 0 193 sec for vertical components our results demonstrated that observed peak ground acceleration pga has prominent distribution in the border cities of up and bihar pga ranges from 3 to 80 cm sec 2 in the study region for the epicentral distance varying from 120 km to 495 km with respect to the source zone mainshock the peak ground velocity pgv varies from 1 to 16 cm sec while the peak ground displacement pgd lies in between 1 cm and 20 cm for the same area our study shows that variation of pgd pgv and pga are controlled and dictated by the geo morphological constraints besides the nature and extent of structural heterogeneities of the sub surface geological formation materials the obtained normalised spectral amplifications are compared with the bureau of indian standard code for construction of buildings which shows that the current indian building design code is within the structural limits proposed for the seismic forces at all periods for alluvium sites suggesting that the structural heterogeneity has the strong role contributing towards the intrinsic attenuation in the seismic wave propagating medium our analysis also shows a good correspondence with the nonlinearity of the seismic waves which in turn controls the degree of damage in an area we infer that extent of damage to the structures in the border cities of india vicinity to the rupture zone can be avoided if the existing building design code could have been implemented as the earthquake risk resilient mitigation plan

luminescence studies on neotectonic events in south central kumaun himalaya a feasibility study abstract results of a feasibility study on luminescence dating of neotectonic events as recorded in fault gouges and buried soils formed on landslide debris are reported it is suggested that clay mineralogical data on illite and chlorite can provide a reasonable estimate on the thermal excursion and hence on resetting of the luminescence clock during faulting the thermoluminescence ages are consistent with the available radiocarbon ages and have been used to infer that naini lake was formed at ca 40 50 ka

cryptochrons and tiny wiggles new magnetostratigraphic evidence from chrons 32 and 33 in western canada abstract magnetostratigraphic results are reported for a deep core that penetrates campanian maastrichtian strata in south central alberta canada chrons 32n 32r and 33n are represented fourteen short reversed polarity magnetozones are present 10 of which are interpreted as new polarity subchrons four in 32n 2n and six in 33n their durations are about an order of magnitude longer than that inferred for the corresponding tiny wiggles observed in marine magnetic anomaly patterns

precursor seismicity foreshocks and aftershocks of the uttarkashi earthquake of october 20 1991 at garhwal himalaya abstract the uttarkashi earthquake m b 6 6 of october 20 1991 occurred in a complicated geological tectonic setting at the main central thrust mct zone of the himalaya the main shock was preceded by a precursory earthquake activity which continued for about eight years and then there was a quiescent period for about three years three foreshocks m 4 0 occurred 48 h before the main shock two aftershocks m 4 0 occurred within 12 h of the main shock which was then followed by another two aftershocks m 4 0 after about seven days on october 27 1991 the largest aftershock m 5 2 occurred within 12 h the aftershocks magnitude less than 4 0 continued for about two months and it decayed at a rate t 0 87 about 1000 earthquakes magnitude less than 1 0 and above were recorded by a closely spaced five station temporary microearthquake meq network out of these 124 aftershocks which occurred inside the network are located by homogeneous station method spatial variation of the aftershocks with time was observed fault plane solutions of the main shock and aftershocks indicate dominantly thrust faulting based on the hypocentral data depth estimate of the plane of detachment is made and a fault interaction model is presented the model shows that the main shock occurred at the juncture of mct zone plane of detachment and the basement thrust the north dipping uttarkashi fault a parallel fault at the mct zone has been activated by the tectonic stress generated due to relative movement of the tibetan plate over the indian plate

transverse tectonics structures in the garhwal himalaya corridor inferred from 3d inversion of magnetotelluric profile data in the garhwal himalayan corridor ghc we recorded the magnetotelluric mt data at 40 sites in three phases out of these 40 sites useful tipper or vertical magnetic field transfer function vtf data was available only at 19 sites the resistivity model obtained from 3d inversion of the mt data is used to investigate the existence of transverse tectonic structures in the garhwal himalaya through a synthetic inversion experiment on scattered data over a profile like our ghc profile we have demonstrated that the mt data can be used to qualitatively infer about the off profile resistivity structures within about 20 km from the profile we carried out several 3d inversion experiments using different subsets of full impedance tensor and vtf responses individually and jointly to arrive at the final resistivity model the 2d profile section of our 3d resistivity model explains the thrust tectonic and flat ramp flat geometry of the main himalayan thrust mht furthermore the inverted model delineated delhi haridwar ridge dhr as a highly resistive 1000 m feature beneath the low resistive 50 m sediments of the indo gangetic plain igp the dhr continues up to the inner lesser himalayan region and it is bounded by two conductive 10 m fluid saturated fractured zones situated off profile and these run nearly parallel to the dhr from the electrical image of the dhr and of the associated conducting feature which have the geoelectric strike of n13 e we inferred that these features are transverse to the main himalayan arc

intensity magnitude location and attenuation in india for felt earthquakes since 1762 a comprehensive consistently interpreted new catalog of felt intensities for india martin and szeliga 2010 this issue includes intensities for 570 earth quakes instrumental magnitudes and locations are available for 100 of these events we use the intensity values for 29 of the instrumentally recorded events to develop new intensity versus attenuation relations for the indian subcontinent and the himalayan region we then use these relations to determine the locations and mag nitudes of 234 historical events using the method of bakun and wentworth 1997 for the remaining 336 events intensity distributions are too sparse to determine mag nitude or location we evaluate magnitude and location accuracy of newly located events by comparing the instrumental with the intensity derived location for 29 cali bration events for which more than 15 intensity observations are available with few exceptions most intensity derived locations lie within a fault length of the instrumen tally determined location for events in which the azimuthal distribution of intensities is limited we conclude that the formal error bounds from the regression of bakun and wentworth 1997 do not reflect the true uncertainties we also find that the regression underestimates the uncertainties of the location and magnitude of the 1819 allah bund earthquake for which a location has been inferred from mapped surface deformation comparing our inferred attenuation relations to those developed for other regions we find that attenuation for himalayan events is comparable to intensity attenuation in california bakun and wentworth 1997 while intensity attenuation for cratonic events is higher than intensity attenuation reported for central eastern north america bakun et al 2003 further we present evidence that intensities of intraplate earth quakes have a nonlinear dependence on magnitude such that attenuation relations based largely on small to moderate earthquakes may significantly overestimate the magnitudes of historical earthquakes

normal polarity magnetosubchrons in 24r and the age of the paleocene eocene boundary a late paleocene to early eocene sequence of flat lying continental strata occurs in an area known as obed mountain west central alberta the upper 110 m consist of interbedded fluvial channel sandstones and overbank mudrocks containing five back swamp coal seams two coreholes 3 5 km apart that extend through the entire coal zone were sampled for magnetostratigraphy and 13c isotope analysis bentonites in the no 1 lowest and no 5 coal seams and a tuff in the no 3 coal seam were sampled for u pb and or rb sr dating of zircon and biotite respectively magnetostratigraphic analysis of 520 samples identified the younger part of chron 25r the whole of chron 25n and the older half of chron 24r we find six normal polarity subzones in this part of chron 24r which we correlate to tiny wiggles 6 to11 in marine magnetic profiles carbon isotope analysis of 14 samples from two cores revealed a negative shift of about 2 peaking near the base of 24r 8r we interpret this as the carbon isotope excursion

study of attenuation mechanism for garwhal kumaun himalayas from analysis of coda of local earthquakes abstract the relative contribution of intrinsic q i 1 and scattering q s 1 attenuation to seismic wave attenuation was estimated for the garwhal kumaun himalayas using multiple lapse time window analysis mltwa method under the assumption of isotropic scattering local earthquake data recorded by an array operated by wadia institute of himalayan geology wihg india was used for this purpose it is observed that scattering attenuation primarily contributes to seismic wave attenuation in this region and its value is much higher compared to that of intrinsic attenuation at around 1 hz frequency as frequency increases the relative contribution of scattering attenuation to total attenuation starts decreasing however as seismic albedo is higher than 0 5 for all the frequencies considered it is concluded that the medium here is highly heterogeneous in nature

assessing the age of the late cretaceous danek bonebed with u pb geochronology an ash rich volcaniclastic sandstone immediately underlying dinosaur rich material from the danek bonebed in the horseshoe canyon formation hcf edmonton alberta canada contains accessory zircon which have been dated employing u pb geochronology both laser ablation inductively coupled plasma mass spectrometry la icp ms and chemical abrasion isotope dilution thermal ionization mass spectrometry id tims u pb analyses have been conducted the zircon age distributions are complex with u pb dates ranging from precambrian to cretaceous we consider the youngest id tims 206pb 238u date of 71 923 0 068 ma as the maximum deposition age of the ash rich sandstone placing the overlying danek bonebed in the early maastrichtian this age is compatible with the paleontological assemblage from the danek bonebed and the regional stratigraphy the zircon age distribution also implies that the hcf had a complex provenance of the detritus with some archean and proterozoic zircons a group of mesozoic and a large compliment of cretaceous grains the results highlight the importance of high precision geochronology in constraining the age of important fossil deposits such as the danek bonebed

macrofossil magnetobiostratigraphy for the upper santonian lower campanian interval in the western interior of north america comparisons with european stage boundaries and planktonic foraminiferal zonal boundaries magnetostratigraphic samples were collected from the milk river and pakowki formations of southeastern alberta to determine the polarity chron 34 33r boundary this boundary was located in the upper half of the deadhorse coulee member and is below the first local occurrence of the western interior ammonite baculites obtusus comparison with the laterally equivalent eagle sandstone of montana and niobrara formation of colorado indicates that the 34 33r contact is within either the baculites sp smooth or baculites sp weak flank ribs ammonite zone in the western interior of north america direct correlation of the desmoscaphites erdmanni through baculites asperifomis western interior ammonite zones with magnetobiostratigraphic sections of the upper santonian lower campanian stages in europe suggests that i the santonian campanian boundary as defined in europe is within the lower baculites obtusus zone and ii the western interior appearance of some ammonites and crinoids scaphites hippocrepis trachyscaphites spiniger marsupites uintacrinus is profoundly time transgressive relative to the appearance of these same species in europe the date of 84 ma for the santonian campanian boundary is too old and a date of around 80 ma may be more accurate the santonian campanian boundary defined by ammonites crinoids and belemnites in europe is within the lower part of chron 33r and is younger than the santonian campanian boundary as determined by planktonic foraminifera at gubbio italy

marine reptiles from the nanaimo group upper cretaceous of vancouver island a new fauna of fossil marine reptiles is described from the late cretaceous nanaimo group of vancouver island the fossils are from the haslam and pender formations upper santonian near courtenay british columbia and include elasmosaurid plesiosaurs turtles and mosasaurs this is only the second fauna of late cretaceous marine reptiles known from the pacific coast the other being from the moreno formation of california maastrichtian the new nanaimo group fossils are some 15 million years older than those from the moreno formation however like the california fauna there are no polycotylid plesiosaurs and one of the mosasaurs is a new genus this reinforces the provinciality of the pacific faunas and their isolation from contemporaneous faunas in the western interior seaway

a new geomagnetic polarity time scale for the late cretaceous and cenozoic we have constructed a magnetic polarity time scale for the late cretaceous and cenozoic based on an analysis of marine magnetic profiles from the world s ocean basins this is the first time since heirtzler et al 1968 published their time scale that the relative widths of the magnetic polarity intervals for the entire late cretaceous and cenozoic have been systematically determined from magnetic profiles a composite geomagnetic polarity sequence was derived based primarily on data from the south atlantic anomaly spacings in the south atlantic were constrained by a combination of finite rotation poles and averages of stacked profiles fine scale information was derived from magnetic profiles on faster spreading ridges in the pacific and indian oceans and inserted into the south ariantic sequence based on the assumption that spreading rates in the south atlantic were smoothly varying but not necessarily constant a time scale was generated by using a spline function to fit a set of nine age calibration points

magnetostratigraphy of the canadian continental drilling program cretaceous tertiary k t boundary project core holes western canada the canadian continental drilling program ccdp cretaceous tertiary boundary project cored three holes to 160 188 and 170 m in southern alberta saskatchewan and manitoba respectively to int

seismotectonic perspectives on the himalayan arc and contiguous areas inferences from past and recent earthquakes abstract spread over countries including pakistan india nepal bhutan and china the himalayan mountain chain the most spectacular result of the indo eurasian plate collision is a locus of destructive earthquakes past earthquakes from this region have impacted vast swathes of frontal himalaya and stretches of alluvial plains south of the range front risk from future earthquakes has increased considering the burgeoning population and an ever expanding built environment in the region while considerable ambiguities exist on the locations ruptures and sizes of the earthquakes during the first half of the last millennium 1255 1344 and 1505 ce those during the latter half 1803 and 1833 ce are quite well documented all reported from the central himalayan segment comprising eastern nepal kumaun and garhwal while dormancy prevailed in the central segment in the intervening period the himalayan arc elsewhere witnessed three large great earthquakes in the last century namely 1905 kangra mw 7 8 1934 bihar nepal mw 8 2 and 1950 upper assam mw 8 6 the last one being the largest intra continental earthquake in the recorded history the april 25 gorkha nepal earthquake mw 7 8 located in the central seismic gap terminated the period of low level seismic productivity that followed the 1950 event the himalayan arc and its contiguous regions are now being investigated using various tools including paleoseismology quite understandably the interpretations and tectonic models do not always converge given the diverse quality and type of data the data from variously sized modern day earthquakes sourced in the diverse structural settings of the himalaya provide better constraints on the source properties of the himalayan earthquakes the source complexity and diversity is a striking point of interest for the post 1950 events and at least some of them seem to deviate from the generally accepted model of great ruptures on a shallow dipping detachment a prime example of such anomalies is the 2005 kashmir earthquake mw 7 6 sourced on an out of sequence thrust the sources of the 1991 uttarkashi mw 6 8 1999 chamoli mw 6 6 and the 2015 gorkha nepal mw 7 8 earthquakes all in the central himalayan segment are attributed to the ramp flat on the down dip part of the main himalayan thrust mht in contrast the 2011 sikkim mw 6 9 and the 2016 imphal mw 6 7 earthquakes are intraplate events sourced within the subducting slab source models of modern day earthquakes 1991 2016 discussed in this paper bring out this plurality of mechanisms expected of a complex subduction cum collisional boundary this review presents the status of current seismotectonic understanding of the himalaya from the analyses of significant earthquakes from the past as well as recent events with a focus on the central himalayan segment

surface motions and continental deformation in the indian plate and the india eurasia collision zone the collision of the indian plate with eurasia has played a major role in controlling the dynamics of central asia leading to the world s largest continental deformation zone in order to study the deformation within the indian plate as well as the india eurasia collision zone we model the lithospheric stress field by calculating the two primary sources of stress one arising due to topography and shallow lithospheric structure estimated by gravitational potential energy differences and the other arising from basal tractions derived from density driven mantle convection we use several tomography models to calculate horizontal tractions using the convection code hc for two radially varying viscosity structures we also take into account lateral viscosity variations in the lithosphere model arising from stiff cratons weak plate boundaries and strength variations due to old and young oceanic lithosphere we do a quantitative comparison of our predicted deviatoric stresses strain rates and plate velocities with surface observables and find that the regional tomography model of singh et al 2014 embedded in the global s wave model s40rts does a remarkable job of fitting the observations of gps velocities and strain rates as well as intraplate stress field from the world stress map

a new erinaceid mammalia insectivora from the late paleocene of western canada a new genus and species of erinaceid lipotyphlan mammalia insectivora from the late paleocene of western canada is described oncocherus krishtalkai gen et sp nov is known from three late tiffanian localities in central alberta and southeastern saskatchewan and is but one of several erinaceomorph and soricomorph taxa known from the late paleocene of western canada oncocherus possesses apomorphies that link it to other primitive erinaceids e g enlarged upper and lower fourth premolars lower molars markedly decreasing in size from m1 m3 talonid basins v shaped yet its affinity with any of the recognized erinaceid subfamilies is uncertain although oncocherus is phenetically and probably phylogenetically closest to litolestes jepsen the genus is clearly distinguished from litolestes and other erinaceid taxa by its proportionately larger and more inflated premolars and lower crowned molars features that were likely adaptations for durophagy oncocherus joins a number of endemic mammalian taxa that were apparently confined to more northerly latitudes of the western interior of north america during the late paleocene

structural control on along strike variation in the seismicity of the northwest himalaya an overview of seismicity along the northwest himalaya exhibit along strike segmentation intricately controlled by the subsurface topographic ridges on the underthrusting indian plate as well by rift and nappe structures in the overriding wedge of the himalaya the segmentation exists for thrust dominated large magnitude earthquakes m 6 seated on the active detachment beneath the outer and lesser himalaya segmentation also prevails for moderate and small magnitude earthquakes concentrated in a narrow himalaya seismic belt hsb straddling northern lesser himalaya and southern higher himalaya numerical calculations of stress distribution favour that the degree of seismicity in the hsb is a good proxy to the presence of mid crustal ramp connecting the locked section of active detachment to aseismically slipping detachment beneath higher himalaya further gap or diffused pattern in the concentrated seismicity in the hsb in agreement with mapped high electrical conductive structure suggests ramp structure may be absent where underthrusting delhi hardwar ridge interacts with the himalaya arc in the nappe dominated tectonics the accommodation of the accumulating strains on the listric thrust faults produces increased frequency of moderate magnitude earthquakes and thereby possibly influences stress level on the detachment this may explain relatively less frequent occurrences of large earthquake in the kangra chamba region compared to that in the garhwal himalaya the low level seismicity in the simla region may also be influenced by the active kaurik chango rift in the higher himalaya as the former casts a stress shadow on the latter

a new centrosaurine ceratopsid from the oldman formation of alberta and its implications for centrosaurine taxonomy and systematics centrosaurus brinkmani sp nov is distinguished from centrosaurus apertus by key features of its cranial ornamentation including the shape and orientation of the postorbital horn and parietal ornamentation at parietal locus 3 the shape of the parietal ornamentation at locus 2 and the possession of accessory parietal ossifications developed as short spines on the caudal parietal ramus this species is restricted to the oldman formation of southern alberta and is the oldest ceratopsid represented by diagnostic material in canada phylogenetic analysis of the centrosaurinae suggests that the development of spike like ornamentation at the parietal locus 3 parietal locus is inversely related to the development of the p1 parietal ornamentation

magnetostratigraphic and biostratigraphic correlation of late campanian and maastrichtian marine and continental strata from the red deer valley to the cypress hills alberta canada two stratigraphic sequences red deer valley and cypress hills sections in alberta spanning the late campanian to paleocene are magnetostratigraphically and biostratigraphically characterized the red deer valley section had previously been studied but additional material has allowed the extension of the magnetozonation downwards into the bearpaw formation higher sample resolution has allowed the identification of a number of magnetosubzones in 32n 32r and 33n four reversed magnetosubzones have been identified in magnetozone 32n in addition to the one presently recognized in geomagnetic polarity time scales one normal subzone in 32r and one reversed subzone in 33n have also been recorded the 32r 33n boundary is shown to occur in the baculites cuneatus zone the campanian maastrichtian boundary is indicated to be at or near the baculites eliasi baculites baculus boundary at the top of 32n comparisons of the biostratigraphy between the two areas indicate that palynomorph ranges differ from data p

first high precision u pb ca id tims age for the battle formation upper cretaceous red deer river valley alberta canada implications for ages correlations and dinosaur biostratigraphy of the scollard frenchman and hell creek formations the battle formation bfm is a widespread upper cretaceous marker horizon in western canada that records a time of low sediment input and marks the boundary between the edmontonian and lancian lan

introduction to the special issue commemorating the 30th anniversary of the royal tyrrell museum of palaeontology with a summary of the museum s early history and its research contributions located just west of drumheller in southern alberta canada the royal tyrrell museum of palaeontology rtmp is nestled among outcrops of the upper cretaceous horseshoe canyon formation exposed along the red deer river valley fig 1 since it officially opened on 25 september 19851 the museum has become one of alberta s must see tourist attractions a significant contributor to the local economy and earned an international reputation for the quality of its palaeontological collections and the research conducted by its scientists the rtmp is unique within canada in being the only government supported museum dedicated to palaeontology and it is one of the few such institutions in the world fig 1 the royal tyrrell museum of palaeontology a front of museum and main entrance circa 2010 looking westwards and with horizontal beds of the upper cretaceous horseshoe canyon formation exposed in the walls of the red deer river valley in the distance b aerial photograph oblique angle and looking to the north northeast the museum sits on top of the number 7 coal seam sensu gibson 1977 and at the base of the horsethief member of the horseshoe canyon formation d a eberth pers comm 2015 that stratigraphic position correlates with an age of about 71 5 ma i e late campanian and lies within the upper part of the edmontosaurus regalis pachyrhinosaurus canadensis dinosaur assemblage zone see eberth et al 2013 fig 6 c the iconic running theropod logo that until recently graced the exterior of the museum below a life sized tyrannosaurid sculpture by brian cooley one of many such sculptures by cooley that have been featured at the museum since its opening in 1985 and with the education wing opened in 2003 as the atco tyrrell learning centre in the background d the cretaceous alberta life sized diorama opened in 2007 an example of a rtmp exhibit that relies heavily on discoveries and interpretations by museum researchers in this case work done in the albertosaurus bonebed and at other localities throughout the horseshoe canyon formation all photographs courtesy of the royal tyrrell museum of palaeontology this special issue of the canadian journal of earth sciences presents a collection of papers commemorating the rtmp s 30th or pearl anniversary our rationale for doing a 30th anniversary volume was two fold first it is an opportunity to showcase the breadth of research conducted by current and former museum scientists as well as by some colleagues having a history of collaboration with the rtmp the 13 invited papers included in this volume are a mix of review and original research papers all thematically focused on the geology and palaeontology of alberta to varying degrees each contribution is the result of work supported by the rtmp and relies on specimens housed in the museum s collections second the 30th anniversary is an opportunity to reflect on the rtmp s history and its research program as is typical for most institutions the rtmp has done little to formally document its own history this year likely will be the last major milestone for which the original generation of museum staff are still working and available to share their recollections about the museum fieldwork and research already deaths and departures have winnowed away part of the original

estimation of source parameters quality factor qs and site characteristics using accelerograms uttarakhand himalaya region abstract a study of source path and site characteristics was conducted for the uttarakhand himalaya region using accelerogram data from 15 earthquakes m l 3 5 these earthquakes were recorded at the 16 station accelerograph network operated by the indian institute of technology roorkee during 2005 2011 the average seismic moment m 0 of the studied earthquakes ranges between 1 20 10 22 and 1 02 10 24 dyn cm and the average moment magnitude m w is between 4 0 and 5 3 the estimated corner frequency f c varies from 1 1 to 3 3 hz radius of rupture r d from 0 5 to 1 4 km and stress drop from 6 to 172 bars indicating continuous seismic energy release in the uttarakhand region the interdependence between estimated source parameters is shown by determining scaling laws for the studied region the constant q 0 of the shear wave quality factor q s q 0 f n varies between 40 and 300 and exponent n varies between 0 85 and 1 5 providing an average relation of q s 174 f 1 27 however least square fitting of the observed data set in the frequency range 0 1 20 hz gives q s as 159 f 1 16 the value of q s demonstrates that the region is heterogeneous seismically active and attenuative the high frequency spectral fall off factor varies from 1 3 to 2 1 and the upper crustal attenuation factor from 0 023 to 0 07 s at different sites with an average of 0 044 s the site response characteristics are estimated by horizontal to vertical spectral ratio hvsr and generalized inversion ginv techniques results obtained from both the techniques show 1 1 correspondence the site amplification factor varies between 2 3 and 9 4 using hvsr and between 2 6 and 10 9 using ginv among different stations the predominant frequency ranges from 1 3 to 8 3 hz with hvsr and from 1 3 to and 9 0 hz with ginv online material tables of source path and site parameters with associated errors at different sites for the earthquakes recorded from december 2005 to march 2011 figures represent accelerogram records source spectra matching and site amplification patterns

dinosaur eggshells from the lower maastrichtian st mary river formation of southern alberta canada north america is known for its rich uppermost cretaceous record of dinosaur egg remains although a notable fossil gap exists during the lower maastrichtian here we describe a diverse dinosaur eggshell assemblage from the st mary river formation of southern alberta that in conjunction with recently described eggs from the same formation in montana helps fill this gap and sheds light on the dinosaur diversity in this poorly fossiliferous formation three theropod eggshell types continuoolithus cf c canadensis montanoolithus cf m strongorum and prismatoolithus cf p levis and one ornithopod spheroolithus cf s albertensis are reported from albertan exposures of the st mary river formation increasing the ootaxonomic diversity of the formation from two to five ootaxa the taxonomic composition of the eggshell assemblage is consistent with the dinosaurian fauna known from the st mary river formation based on skeletal remains spheroolithus eggshells constitute the majority of identifiable e

terrestrial palynomorph biostratigraphy of the cypress hills wood mountain and turtle mountain areas upper cretaceous paleocene of western canada three cored test holes were drilled to study the stratigraphic interval spanning the cretaceous tertiary boundary one in the western cypress hills near elkwater alberta a second in the eastern portion of the wood mountain area near killdeer saskatchewan and a third on the western edge of turtle mountain near goodlands manitoba the terrestrial elements of the palynological assemblages are discussed the maastrichtian assemblages encompassed the scollardia trapaformis zone and two new subzones myrtipites scabratus aquilapollenites delicatus var collaris and porosipollis porosus aquilapollenites notabile within the wodehouseia spinata zone the paleocene zones encountered include the aquilapollenites reticulatus subzone of the w spinata zone the previously described wodehouseia fimbriata and momipites wyomingensis zones and the newly defined tricolporopollenites kruschii zone these provide a biostratigraphy for the cored intervals which can be related to polarity chrons the observations mad

summary of fossil vertebrate taxa named by richard c fox with an annotated list of taxa named between 1962 and 2012 and new photographs for non mammalian therapsid and mammalian holotypes erected between 1968 and 1994 beginning in 1962 and extending to the present richard c fox and colleagues have named 87 species of fossil vertebrates 1 fish 4 amphibians 2 choristoderes 12 lizards 1 crocodile 1 dinosaur 2 pelycosaurs 2 non mammalian therapsids and 62 mammals and numerous new supraspecific taxa virtually all of these species continue to be accepted although the higher level assignments of several have been altered the vast majority of the named species were founded on specimens collected during the mid 1960s to early 2000s by field parties under fox s direction from the late cretaceous late santonian to late maastrichtian and paleocene of alberta and saskatchewan canada and that are housed at the university of alberta laboratory for vertebrate paleontology here we present i an annotated list of all fossil vertebrate species named by richard fox between 1962 and 2012 ii updated information on the stratigraphic nomenclature and age estimates for the eight localities in alberta that yielded ho

on the possibility of reservoir induced seismicity in the garhwal himalaya chander r 1991 on the possibility of reservoir induced seismicity in the garhwal himalaya eng geol 30 393 399 it is argued from a brief review of available evidence that the possibility of reservoir induced seismicity ris in the himalaya as a whole cannot be ruled out at the present time on the other hand a review of recent local investigations of small earthquakes mb less than 5 and teleseismic investigations of moderate earthquakes mb between 5 and 6 mainly occurring in the garhwal segment of the alpide himalayan seismic belt provides evidence that ris in the region can be anticipated while their epicentral belts coincide geographically the estimated focal depths of small and moderate earthquakes of the garhwal himalaya are in the ranges of 0 14 and 10 20 km respectively small earthquakes occur by reactivation of strike slip and reverse faults and moderate earthquakes occur on thrust faults elsewhere in the world ris has been observed most often in the crust at the depths where small earthquakes have been observed in the garhwal himalaya in addition ris has been experienced during the impoundment of reservoirs in strike slip and reverse fault environments while theoretical analyses indicate that if suitably located in relation to the reservoir even a thrust fault may be destabilised by impoundment

late cretaceous to early tertiary magnetostratigraphy of a continental sequence red deer valley alberta canada the red deer valley exposes a conformable 350 m thick late campanian to early paleocene fluvial deltaic coal bearing sequence named the edmonton group systematic sampling and paleomagnetic analysis of the dominant lithologies mudstones sandstones and shales were carried out over five sections correlated by coal seams to provide some 500 sites stratigraphic levels primary detrital remanent magnetization directions after alternating field cleaning produce a polarity reversal pattern correlatable to sea floor magnetic anomalies 29 33 the campanian maastrichtian boundary based upon the first appearance of wodehouseia and the maastrichtian paleocene cretaceous tertiary boundary based upon an ir anomaly associated with dinosaur and cretaceous palynofloral extinctions correlate closely magnetostratigraphically with the marine foraminiferal section at gubbio italy radiometric dating of bentonites has indicated the ages of these boundaries to be approximately 71 and 64 ma respectively

evidence of an asia to north america dispersal of palynomorphs in the late cretaceous the fossil pollen genus morinoipollenites has been frequently reported in strata from the upper cretaceous of northern china and southeastern russia pollen grains belonging to a single fossil species morinoipollenites normalis have been only rarely encountered in upper cretaceous strata of north america just five specimens of morinoipollenites have been recovered from sites of definite or probable maastrichtian age in alaska alberta saskatchewan and colorado it is argued that the rarity in north america common asian occurrences large size of pollen grains and complex morphology of the pollen favour these pollen grains having been transported to north america from asia by some vector the transporting vector would most likely have been a flying organism based on the life styles of the producing plants and transporting organisms long distance of transport and morphology of the pollen grains