the relationship between shellbed type and sequence architecture examples from japan and new zealand abstract examples of lithology fossil content and taphonomic features of shellbeds and intervening less fossiliferous intervals are presented from four plio pleistocene successions shimosa group boso peninsula omma formation hokuriku area japan and okehu kai iwi and shakespeare groups in wanganui and the rangitikei group along the rangitikei river in new zealand as for pre pliocene 3rd and 4th order depositional sequences plio pleistocene 5th to 7th order depositional sequences contain a variety of shellbeds which are often associated with surfaces or intervals that are characterized by sedimentary condensation omission or erosion e g sequence boundaries ravinement surfaces downlap surfaces and condensed sections stratigraphic patterns of shellbed type tend to be similar and repetitive within a basin and a locality this demonstrates that a specific palaeogeography played an important role in determining the nature of shellbeds for example shellbeds formed in the context of toplap are common only in the shimosa group which was deposited in a moderately sheltered sea the palaeo tokyo bay toplap shellbeds are rare in other sequences formed in more open conditions despite the variability resulting from such basin characteristics common styles of shellbeds can be recognized that formed under conditions of marine onlap backlap downlap and toplap each type of shellbed has a characteristic fossil composition and taphonomy onlap and toplap shellbeds contain low diversity macrobenthic associations including glycymeris mercenaria paphies or other bivalves having robust shells which are often abraded or fragmented backlap shellbeds which are equivalent to the condensed section formed at the maximum transgression are characterized by dominance of epifaunal macrobenthos such as bryozoa brachiopoda pectinid and ostreid bivalves preserved in a slightly cemented glauconitic muddy matrix in contrast to fossils in such condensed sections the shell density and species diversity of downlap shellbed associations are rather low and in a few examples the macrobenthic association was buried rapidly in a lower unit of the highstand systems tract hst stratigraphically located above the condensed sections variations in the stratigraphic distribution of shellbed types are reflected in symmetrical and asymmetrical sequence architectures symmetrical sequences have roughly the same thickness of transgressive systems tracts tst and highstand systems tracts hst and have well segregated shellbeds that were formed during marine onlap and backlap asymmetrical cycles have very thin tsts and much thicker hsts and are characterized by the amalgamation of condensed onlap and backlap shellbeds such contrasting cycle architectures are interpreted to reflect inner symmetrical and outer asymmetrical shelf palaeodepositional settings the amalgamated onlap backlap shellbeds appear to be common in plio pleistocene sequences owing to the short duration of glacio eustatic sea level changes with dominant frequencies of 20 000 40 000 or 100 000 years shellbeds in the plio pleistocene are relatively simple and thin compared to those formed in ordinary third order depositional sequences infauna dominated benthic associations are generally more common than in third order cycles and epifaunal associations facilitated by taphonomic feedback on sediment starved shell gravel substrates occur only in the condensed section corresponding to maximum transgression in most plio pleistocene sequences

deep seated gravitational slope deformations related landslides and tectonics abstract deep seated gravitational slope deformations and their relationships with tectonic deformation of rocks is considered to examine the viewpoint of tectonics as a causative factor in slope deformation first a distinction is made between the different types of deep seated gravitational slope deformation then the geomorphological and structural effects of the different macrostructural deformations induced by tectonics on the scale of the whole deforming ridge is briefly discussed finally some case studies that represent either verified or possible cases of gravity deformation in response to tectonic activity are used as illustration

ice moraine and landslide dams in mountainous terrain we review recent work on ice moraine and landslide dams in mountainous terrain thus complementing several comprehensive summaries on glacier dams in intracontinental and arctic areas of low relief we discuss the roles of tectonic and climatic forcing on ice moraine and landslide dam formation and sudden drainage and focus on similarities and differences between their geomorphic impacts on confined valleys drained by steep bedrock and gravel bed rivers despite numerous reported failures of natural dams in mountain belts throughout the world their relevance to long term dynamics of mountain rivers remains poorly quantified all types of dams exert local base level controls thus trapping incoming sediment and inhibiting fluvial bedrock incision pervasive geomorphic and sedimentary evidence of outburst events is preserved even in areas of high erosion rates suggesting that sudden dam failures are characterized by processes of catastrophic valley floor aggradation active channel widening and downstream dispersion of sediment during which little bedrock erosion seems to be achieved we find that in the absence of direct evidence of former dams a number of similarities among the geomorphic and sedimentologic characteristics of catastrophic outburst flows may give rise to ambiguous inferences on the dam forming process this is especially the case for tectonically active mountain belts where there is ample and comparable potential for the formation and failure of ice moraine landslide and polygenetic dams concomitant with climatic oscillations or earthquake disturbance hence the palaeoclimatic implications of erroneously inferring the cause of dam formation may be significant we recommend that future research on natural dams in mountainous terrain addresses a climate and earthquake controlled systematics in the pattern of formation and failure b quantification of response of mountain rivers to catastrophic outburst events and their concomitant process sequences c elaboration of a comprehensive classification of natural dams in mountainous terrain with special attention to polygenetic dams d physical based modelling of dam formation failure and routing of water and sediment outbursts and e quantitative controls on the contribution of natural dams to sediment budgets in mountainous terrain

evidence of large scale deformation patterns from gps data in the italian subduction boundary abstract we present the velocity field in italy derived from over 300 continuous gps stations operated in the 1998 2009 time span the gps network maps the whole country with a mean inter site distance of about 50 km and provides a valuable source of data to study the ongoing deformation processes in the central mediterranean the estimated horizontal and vertical velocity fields show major significant features and also less known second order kinematic features a general uplift characterizes the whole apennines and alpine belts that follow the topographic ridge whereas the po plain shows a gradually increasing subsidence from west to east the apennines belt displays a distinctive extension 50 80 10 9 yr 1 while compressive tectonic regimes characterize northern sicily eastern alps and the northeast front of the northern apennines 25 50 10 9 yr 1 second order deformation patterns on large scale wavelength 100 km have been detected on the accretionary prism of central and southern apennines that are highly correlated with other geophysical data vp anomalies seismic anisotropy etc and related to deep rooted sections 70 100 km marked by different subduction regimes apparently at this scale length the observed deformations are governed by the lithosphere as a whole we interpret these deformations as a result of different subduction mechanisms such as variations of the subduction rollback velocity affecting different segments of the subduction zone and or to mantle flows in proximity of the slab edges further south in central southern sicily we detect a contraction of 1 1 0 2 mm yr that probably accommodates part of the africa eurasia convergence on the outer thrust front of the apennines maghrebides belt this hypothesis agrees with an independent analysis of the seismicity associated to the sicilian basal thrust thought to be still active the itrf2005 estimates of the new gps velocity field are available also in sinex format as supplementary file s1

sequence stratigraphy of the punta ballena member of the jama formation early pleistocene ecuador insights from integrated sedimentologic taphonomic and paleoecologic analysis of molluscan shell concentrations abstract early pleistocene strata are well exposed along the uplifted eastern margin of the esmeraldas caraquez basin particularly on the coastal cliff west of the city of jama a type locality for shallow marine quaternary sedimentary exposures on north central ecuador here at least 180 m of sediments accumulated in inner shelf to subaerial settings are present jama formation this paper is concerned with the middle stratigraphic unit of the jama formation the punta ballena member pbm integrated sedimentologic paleontologic and stratigraphic observations reveal that the pbm is composed of eight disconformity bounded depositional sequences hiatal shell concentrations which formed as a consequence of landward and seaward stratal attenuation are associated with sequence bounding and intrasequence surfaces together with sedimentologic characteristics these fossiliferous levels are important indicators of facies architecture and therefore are useful tools for interpreting sequence stratigraphy according to their taphonomic features and taxonomic composition the hiatal shell concentrations occurring within the pbm may be grouped into two main types each of which occupies a predictable stratigraphic position within the sequences current wave winnowed beds at the cycle base and community shell concentrations in a roughly mid cycle position current wave winnowed beds commonly underlain by thalassinoides burrows that penetrate to depths of as much as 1 5 m below ravinement surfaces are transported skeletal concentrations and formed through physical processes in shallow high energy environments they comprise a time averaged mixture of specimens having different ecologies and states of preservation and accumulated mainly under conditions of total passing of siliciclastic sediment i e terrigenous sediments are delivered to the site as suspended load but owing to the high environmental energy failed to accumulate community shell concentrations occur in sparsely fossiliferous intervals and result from reduced net sedimentation within low energy relatively deeper settings they are composed of matrix supported loosely clustered life oriented and little disturbed fossil assemblages but are packed in excess of likely living densities and are visually dominated by successive generations of the infaunal bivalve raeta undulata which colonized a slowly aggrading muddy seafloor the sedimentological and paleontological evidence presented here not only supports the results of previous studies which demonstrate the value of condensed shell concentrations in the identification of stratigraphically significant surfaces but also provides adds to the distinctive features of these shell beds

developments in the characterization of complex rock slope deformation and failure using numerical modelling techniques recent advances in the characterization of complex rock slope deformation and failure using numerical techniques have demonstrated significant potential for furthering our understanding of both the mechanisms processes involved and the associated risk this paper illustrates how rock slope analyses may be undertaken using three levels of sophistication level i analyses include the conventional application of kinematic and limit equilibrium techniques with modifications to include probabilistic techniques coupling of groundwater simulations and simplistic treatment of intact fracture and plastic yield such analyses are primarily suited to simple translational failures involving release on smooth basal rear and lateral surfaces where the principle active damage mechanisms are progressive failure and or asperity breakdown level ii analyses involve the use of continuum and discontinuum numerical methods in addition to simple translation level ii techniques can be applied to complex translational rock slope deformations where step path failure necessitates degradation and failure of intact rock bridges along basal rear and lateral release surfaces active damage processes in this case comprise not only strength degradation along the release surface e g asperity breakdown but also a significant component of brittle intact rock fracture level iii analyses involve the use of hybrid continuum discontinuum codes with fracture simulation capabilities these codes are applicable to a wide spectrum of rock slope failure modes but are particularly well suited to complex translation rotational instabilities where failure requires internal yielding brittle fracturing and shearing in addition to strength degradation along release surfaces through a series of rock slope analyses the application of varied numerical methods are discussed particular emphasis is given to state of the art developments and potential use of level iii hybrid techniques d 2005 elsevier b v all rights reserved

fault scarps and deformation rates in lazio abruzzo central italy comparison between geological fault slip rate and gps data abstract we compare new and literature data concerning the integrated deformation rate since 18 ka for the central apennines with deformation rate data derived from a 6 year gps campaign we constructed topographic profiles across the majority of the active faults in the area we derived deformation rate data from displaced post glacial sediments and slopes associated with the last major glacial retreat that occurred in the region about 18 kyr ago paleoseismic investigations in this region clearly show that offset of these features is the cumulative effect of repeated surface faulting earthquakes with magnitudes in the range 5 5 ms 7 0 a cumulative throw rate diagram incorporating both our values and the values extracted from the literature i e previously published trenching studies scarp profiles and offset terraces is presented providing a regional picture of the spatial deformation rate distribution in the central apennines during the latest pleistocene and holocene by converting cumulative throw rates into heave rates we calculate maximum extension rates of ca 2 mm year at the location of the same transect where 6 2 mm year has been measured with gps over 6 years this discrepancy between geodetic and geological fault slip rate data implies that we have to be cautious whenever we use gps data for seismic hazard assessment purposes or when attempting to reconstruct the tectonic processes in an area because geodetic data may be unrepresentative of the longer term deformation rates on the other hand this discrepancy may provide insights into the mechanics of the seismic cycle we discuss various scenarios that may explain the mis match between long term and short term measurements

propagation of the deformation and growth of the tibetan himalayan orogen a review abstract long standing problems in the geological evolution of the tibetan himalayan orogen include where the india asia convergence was accommodated and how the plateau grew to clarify these problems we review the deformations and their role in the plateau s growth our results show that 1630 km of shortening occurred across the tibetan himalayan orogen since 55 ma with more than 1400 km accommodated by large scale thrust belts these thrust belts display an outward expansion from central tibet and couple with the surficial uplift the development of the tibetan plateau involved three significant steps primitive plateau 90 55 ma proto plateau 55 40 ma and neoteric plateau 40 0 ma several processes have collaborated to produce the proto plateau including the pre existing primitive plateau the india asia collision and subductions of greater india and songpan ganzi beneath the lhasa qiangtang terrane since 40 ma the proto plateau which was dominated by a topographic gradient lower crustal flow and continuous india asia convergence experienced three periods of rapid outward growth 40 23 23 10 and 10 0 ma in general the n s trending rifts were caused by the eastward growth of the plateau dominated by thrusting and crust flow in central tibet while they were the results of intense n s shortening in himalaya

the formation and failure of natural dams of the numerous kinds of dams that form by natural processes dams formed from landslides glacial ice and late neoglacial moraines present the greatest threat to people and property landslide dams form in a wide range of physiographic settings the most common types of mass movements that form landslide dams are rock and debris avalanches rock and soil slumps and slides and mud debris and earth flows the most common initiation mechanisms for dam forming landslides are excessive rainfall and snowmelt and earthquakes landslide dams can be classified into six categories based on their relation with the valley floor type i dams 11 of 184 landslide dams from around the world that we were able to classify do not reach from one valley side to the other type ii dams 44 span the entire valley floor in some cases depositing material high on opposite valley sides type iii dams 41 move considerable distances both upstream and downstream from the landslide failure type iv dams 1 are rare and involve the contemporaneous failure of material from both sides of a valley type v dams 1 also are rare and are created when a single landslide sends multiple tongues of debris into a valley and forms two or more landslide dams in the same reach of river type vi dams 3 involve one or more failure surfaces that extend under the stream or valley and emerge on the opposite valley side many landslide dams fail shortly after formation in our sample of 73 documented landslide dam failures 27 of the landslide dams failed less than 1 day after formation and about 50 failed within 10 days over topping is by far the most common cause of failure the timing of failure and the magnitude of the resulting floods are controlled by dam size and geometry material characteristics of the blockage rate of inflow to the impoundment size and depth of the impoundment bedrock control of flow and engineering controls such as artificial spill ways diversions tunnels and planned breaching by blasting or conventional excavation glacial ice dams can produce at least nine kinds of ice dammed lakes the most dangerous are lakes formed in main valleys dammed by tributary glaciers failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam cold polar ice dams generally drain supraglacially or marginally by downmelting of an outlet channel warmer temperate ice dams tend to fail by sudden englacial or subglacial breaching and drainage late neoglacial moraine dammed lakes are located in steep mountain areas affected by the advances and retreats of valley glaciers in the last several centuries these late neoglacial dams pose hazards because 1 they are sufficiently young that vegetation has not stabilized their slopes 2 many dam faces are steeper than the angle of repose 3 these dams and lakes are immediately downslope from steep crevassed glaciers and near vertical rock slopes and 4 downstream from these dams are steep canyons with easily erodible materials that can be incorporated in the flow and increase flood peaks the most common reported failure mechanism is overtopping and breaching by a wave or series of waves in the lake generated by icefalls rockfalls or snow or rock avalanches melting of ice cores or frozen ground and piping and seepage are other possible failure mechanisms natural dams may cause upstream flooding as the lake rises and downstream flooding as a result of failure of the dam although data are few for the same potential energy at the dam site ownstream flood peaks from the failure of glacier ice dams are smaller than those from landslide moraine and structed earth fill and rock fill dam failures moraine dam failures appear to produce some of the largest downstream flood peaks for potential energy at the dam site greater than 1011 1012 joules differences in flood peaks natural dam failures appear to be controlled by dam characteristics and failure mechanisms

present day stress in the surroundings of 2009 l aquila seismic sequence italy summary the axial zone of the apenninic belt in central italy is a tectonically active region affected by post orogenic quaternary extension the present day stress field is characterized by a minimum horizontal stress shmin ne sw oriented derived mainly from earthquake focal mechanisms and secondarily from borehole breakouts and fault data the paper describes the computation of the shmin orientation along two deep boreholes located in the vicinity of the area hit by the 2009 april 6 mw 6 3 l aquila earthquake the analysed wells show breakout zones at a depth range between 1 4 and 4 6 km giving precious information on a depth interval usually not investigated by any other data the results show an shmin n81 22 and n74 10 oriented for varoni 1 and campotosto 1 wells respectively the comparison among the breakouts the 2009 seismic sequence the past seismicity and the quaternary faults indicates a small rotation of shmin orientation from ne in the southern to ene in the northern sector of the study area where the wells are located these differences are linked both to the natural variations of data and to the orientation of the main tectonic structures varying from nw se in the abruzzi region to n s moving toward the umbro marchean apennines the identification of constant shmin orientations with depth derived from all the examined active stress data confirms the breakouts as reliable stress indicators also for aseismic areas

unravelling the complexity of apenninic extensional fault systems a review of the 2009 l aquila earthquake central apennines italy the 2009 l aquila sequence activated a normal fault system 50 km long in the central apennines composed of two main nw trending faults 12 16 km long the main high angle l aquila segment and the campotosto listric fault the mw 6 1 l aquila mainshock nucleated on the paganica fault at a depth of 8 6 km and cut through the upper crust producing coseismic surface slip of up to 10 cm observed along a strike length of 13 km analysis of historical seismicity and data collected in paleo seismological trenches suggest that this event filled a 500 year gap in contrast the blind campotosto listric fault is composed of different fault segments displaying abrupt changes in dip at a depth where major events nucleate suggesting a rheological and geometrical control on stress concentration a foreshock sequence that started around 4 months before the l aquila mainshock activated the deepest portion of the paganica fault and marked the onset of large variations in elastic properties of the crustal volume the variations have been modelled in terms of dilatancy and diffusion processes corroborating the hypothesis that fluids play a key role in the nucleation process of extensional faults in the crust

the interaction between active normal faulting and large scale gravitational mass movements revealed by paleoseismological techniques a case study from central italy paleoseismological techniques have been applied to characterize the kinematic behaviour of large scale gravitational phenomena located in proximity of the seismogenic fault responsible for the mw 7 0 1915 avezzano earthquake and to identify evidence of a possible coseismic reactivation the above mentioned techniques were applied to the surface expression of the main sliding planes of the mt serrone gravitational deformation located in the southeastern border of the fucino basin central italy the approach allows us to detect instantaneous events of deformation along the uphill facing scarp these events are testified by the presence of faulted deposits and colluvial wedges the identified and chronologically constrained episodes of rapid displacement can be probably correlated with seismic events determined by the activation of the fucino seismogenic fault affecting the toe of the gravitationally unstable rock mass indeed this fault can produce strong short term dynamic stresses able to trigger the release of local gravitational stress accumulated by mt serrone s large scale gravitational phenomena the applied methodology could allow us to better understand the geometric and kinematic relationships between active tectonic structures and large scale gravitational phenomena it would be more important in seismically active regions since deep seated gravitational slope deformations can evolve into a catastrophic collapse and can strongly increase the level of earthquake induced hazards

holocene landslide dammed lake deposits in the upper jinsha river se tibetan plateau and their ages in the zhongzaebatang segment of the upper jinsha river in the southeast of the tibetan plateau there are eight old landslide dams with nearby associations of relict landslides lacustrine sediments and fluvial sediments associations of this kind provide key evidence for identifying the lacustrine sediments as landslide dammed lake deposits the 14 c ages of 12 samples and the osl ages of 9 samples show that the landslide dammed lake deposits formed during a period of about 122 ade1100 ad corresponding to the time of the late donghan dynasty to the middle of the song dynasty landslides that formed the landslide dammed lake deposits are inferred to be due to earthquakes triggered by active faults

hangingwall surface subsidence at the kiirunavaara mine sweden large scale surface subsidence has been experienced at the kiirunavaara mine since sublevel caving was implemented as a mining method surface disturbances are affecting part of the city of kiruna the railway and the power station continuous and discontinuous subsidences characterize the hangingwall deformation which is periodically monitored using surveying techniques and mapping of surface cracks a historic review of subsidence prognoses has been carried out and the results compared with the actual condition of the hangingwall the review showed discrepancies between different prognoses in addition limit equilibrium analyses indicated that break angles flatten while the mining depth increases however this tendency is not clear in the field where break angles show a large dispersion of values by using surveying data two different analyses have been performed the time dependent movements of the hangingwall have been described using time displacement curves and strain analysis has been performed for different sections of the hangingwall three different stages of the time displacement behavior have been identified and described it has been concluded that extension strain can reach values which may damage civil structures before surface crack can be observed

mass movements along a rapidly uplifting river valley an example from the upper jinsha river southeast margin of the tibetan plateau because of the rapid uplift of the tibetan plateau since the middle and late pleistocene the surrounding mountainous areas of the tibetan plateau also show a rapid uplift trend the study area is located in the upper reaches of the jinsha river southeastern tibetan plateau tectonically the study area is located in the eastern segment of the jinshajiang suture zone which is the weak belt of the lithosphere affected by the rapid uplift steep slopes are formed by the rapid vertical down cutting of rivers in the studied reach under the sustained action of the gravitational field the deformation and failure of slopes readily occur to better formulate development and risk mitigation plans a mass movement inventory map at the scale of 1 50 000 was prepared for the 100 km long reach a total of 247 mass movements of different types sizes and relative ages were mapped via image interpretation and detailed field survey the statistical analysis of their spatial distributions was performed using two relative concentration indexes the correlations between the spatial distribution and six common factors were analyzed elevation slope angle slope aspect lithology active fault and river system the geomorphological survey shows that the mass movements locally play an important role in the present day landscape evolution in addition the geomorphic features indicate that the mapped giant landslides can be classified as very old landslides and they very likely occurred under a different morphoclimatic environment than that of the present

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

inferred bivalve response to rapid burial in a pleistocene shallow marine deposit from new zealand abstract orientations of 16 species of conjoined bivalves were analysed in relation to the sedimentary history of the middle pleistocene upper castlecliff shellbed and the overlying karaka siltstone in wanganui basin new zealand the shellbed represents mid cycle condensation and the karaka siltstone highstand systems tract was deposited by coastal progradation most of the shell orientations represent either life orientation or reworked reclining orientation however orientations inverted compared to the normal feeding position are not uncommon for infaunal shallow burrowing bivalves such as notocallista multistriata but only in the lower unit of the karaka siltstone this orientation is interpreted as produced by upward migration of bivalves when they were buried rapidly such bivalve orientations are evidence for a rapid change in sedimentation rate from the starved condition represented by the midcycle condensed shellbed upper castlecliff shellbed across a downlap surface to the highstand systems tract karaka siltstone where episodic rapid sedimentation began

active normal faulting along the mt morrone south western slopes central apennines italy in the present work we analyse one of the active normal faults affecting the central apennines i e the mt morrone normal fault system this tectonic structure which comprises two parallel nw se trending fault segments is considered as potentially responsible for earthquakes of magnitude 6 5 and its last activation probably occurred during the second century ad structural observations performed along the fault planes have allowed to define the mainly normal kinematics of the tectonic structure fitting an approximately n 20 trending extensional deformation geological and geomorphological investigations performed along the whole mt morrone south western slopes permitted us to identify the displacement of alluvial fans attributed to middle and late pleistocene by means of tephro stratigraphic analyses and geomorphological correlations with dated lacustrine sequences along the western fault branch this allowed to evaluate in 0 4 0 07 mm year the slip rate of this segment on the other hand the lack of synchronous landforms and or deposits that can be correlated across the eastern fault segment prevented the definition of the slip rate related to this fault branch nevertheless basing on a critical review of the available literature dealing with normal fault systems evolution we hypothesised a total slip rate of the fault system in the range of 0 4 0 07 to 0 8 0 09 mm year moreover basing on the length at surface of the mt morrone fault system i e 22 23 km we estimated the maximum expected magnitude of an earthquake that might originate along this tectonic structure in the order of 6 6 6 7

identification of ancient river blocking events and analysis of the mechanisms for the formation of landslide dams in the suwalong section of the upper jinsha river se tibetan plateau abstract the suwalong section of the upper jinsha river is located on the southeastern margin of the tibetan plateau affected by the rapid uplift of the tibetan plateau steep slopes have been formed by the rapid downcutting of rivers in this section tectonically the suwalong section is located in the jinshajiang suture zone and features intense tectonic activity making this section prone to geological disasters such as landslides through field investigation four old accumulation bodies were found in the suwalong section and lacustrine sediments were observed upstream of these bodies by analysing the surrounding landforms appearance features and internal rocks of the old accumulation bodies we conclude that these four old accumulation bodies represent the remains of dams that blocked the river these dams formed through the deposition of rockslides rock avalanches or debris flows that occurred on the slopes on both sides of the river by comparing the top elevation information and the chemical and mineral compositions of the lacustrine sediments around these residual dams the order of the demise of two dammed lakes was obtained and the order was confirmed by optically stimulated luminescence osl dating the method in this paper has great applicability for identifying river blocking events in other regions

extensional basins in the tectonically bimodal central apennines fold thrust belt italy response to corner flow above a subducting slab in retrograde motion the apennines fold thrust belt has developed over the past 20 m y in response to southeastward retrograde migration of the adriatic trench in a region of ongoing subduction but little plate convergence the orogenic belt is characterized by a gently sloping southwestern flank in a state of regional extensional collapse and a steeply sloping northeastern flank in regional contraction in any given area in the central apennines the chronologies of thrusting and subsequent extension provide an estimate of the time required for attainment of high elevation 2 5 3 0 km the time between initial extension and eruption of local ultramafic lavas provides an estimate of the time required to collapse by regional crustal thinning these estimates suggest that the northeastern contractional flank of the range is rising at least twice as fast as the southwestern flank is collapsing we propose that the bimodal state of stress in the apennines is maintained by corner flow in the mantle wedge beneath the crest of the range

the 2009 l aquila earthquake italy what s next in the region hints from stress diffusion analysis and normal fault activity abstract this work aims at defining the contribution in terms of earthquake probability assessment of the integration of coulomb stress diffusion analysis related to an earthquake with geological studies on fault activities investigating the case of the april 6 2009 l aquila central italy earthquake mw 6 3 the analysis of the coulomb stress diffusion induced by this earthquake has revealed a stress increase along two poorly investigated active normal faults in the apennines the subequana fault and the middle aterno valley fault no strong seismic events have been attributed to these tectonic structures over the past 800 1000 yr and they have therefore been considered as probable seismic gaps geological and paleoseismological investigations have since indicated that these tectonic structures belong to the same 25 30 km long fault system that ruptured twice during the late holocene the last activation occurred between the 4th 1st century b c and the past millennium probably during the 2nd 1st century b c with the penultimate between 6381 30 bp and 3511 37 bp the data obtained indicate that this fault system might rupture in up to magnitude 6 8 earthquakes and that the 2009 seismic event has brought these tectonic structures about 200 yr closer to failure

the 1786 earthquake triggered landslide dam and subsequent dam break flood on the dadu river southwestern china abstract chinese historic documents recorded that on june 1 1786 a strong m 7 75 earthquake occurred in the kangding luding area sichuan southwestern china resulting in a large landslide that fell into the dadu river as a result a landslide dam blocked the river ten days later the sudden breaching of the dam resulted in catastrophic downstream flooding historic records document over 100 000 deaths by the flood this may be the most disastrous event ever caused by landslide dam failures in the world although a lot of work has been carried out to determine the location magnitude and intensity of the 1786 earthquake relatively little is known about the occurrence and nature of the landslide dam in this paper the dam was reconstructed using historic documents and geomorphic evidence it was found that the landslide dam was about 70 m high and it created a lake with a water volume of about 50 106 m3 and an area of about 1 7 km2 the landslide dam breached suddenly due to a major aftershock on june 10 1786 the peak discharge at the dam breach was estimated using regression equations and a physically based predictive equation the possibility of a future failure of the landslide seems high particularly due to inherent seismic risk and detailed geotechnical investigations are strongly recommended for evaluating the current stability of the landslide

a methodological approach for the analysis of the temporal occurrence and triggering factors of landslides the temporal occurrence of landslides in an area of the cantabrian range during the last 120 000 years is analyzed an initial relative chronology was established on the basis of aging degree and spatial relationships between landslides and glacial and fluvial features ten landslide classes were thus identified and their chronological limits defined on the basis of 19 14c age determinations on fluvial and glacial deposits including eight new ones the chronology was tested with 14c dates obtained on landslide deposits 10 from previous work and nine new ones the chronological classes identified were compared with existing climate models for the region the type and spatial distribution of landslides in each class were also analyzed the approach made it possible to identify periods during which landslides were triggered mainly by channel incision seismic activity and rainfall increase human activity played a significant role after 5000 bp and especially in the last few centuries mobilization of materials by slope movements has increased in the region by a factor of 10 compared to pre neolithic rates

the 2009 l aquila central italy mw6 3 earthquake main shock and aftershocks 1 a m w 6 3 earthquake struck on april 6 2009 the abruzzi region central italy producing vast damage in the l aquila town and surroundings in this paper we present the location and geometry of the fault system as obtained by the analysis of main shock and aftershocks recorded by permanent and temporary networks the distribution of aftershocks 712 selected events with m l 2 3 and 20 with m l 4 0 defines a complex 40 km long nw trending extensional structure the main shock fault segment extends for 15 18 km and dips at 45 to the sw between 10 and 2 km depth the extent of aftershocks coincides with the surface trace of the paganica fault a poorly known normal fault that after the event has been quoted to accommodate the extension of the area we observe a migration of seismicity to the north on an echelon fault that can rupture in future large earthquakes

large scale landslides triggered by quaternary tectonics in the acambay graben mexico detailed analysis was conducted on large scale gravitational tectonic deformations and landslides in the acambay graben an intra arc basin in the trans mexican volcanic belt tmvb field mapping and remote sensing revealed the slope instability of the northern graben boundary induced by the acambay tixmadeje fault two major landslides of 0 1 km3 and 0 05 km3 in volume were identified and their characteristics were analyzed according to the role of tectonics mechanism of slope failure and possible triggering factors quaternary faulting played a major role in increasing the local relief and the activity of the acambay tixmadeje fault represents the main geomorphic factor conditioning the gravitational movements moreover displacements along this fault generated sliding surfaces and reduced the strength of the rock mass the two landslides are classified as large scale rotational slides involving volcanic rocks of late miocene pleistocene age since the acambay graben is a seismogenic area with a known maximum horizontal ground acceleration of 0 5 g a strong earthquake could be ascribed as the possible triggering mechanism of the landslides our work represents the first analysis of large gravitational slope movements in tectonically active regions in mexico a process that can be common in the intra arc basins of the tmvb where active tectonic seismicity weak altered volcanic rocks and heavy rains affect the slope stability copyright 2010 john wiley sons ltd

palaeoecological effects of back arc spreading on miocene benthic communities sw japan arc abstract during the early to middle miocene rapid development of backarc basins now known as the sea of japan occurred in the ne margin of the asian continent then the entire sw japan arc the arc was rotated clockwise very rapidly such an event was associated with the opening of another backarc basin located to the south of the arc immediately after this opening the very young hot oceanic plate began to subduct underneath the arc this subduction caused rapid uplifting and enhanced the denudation of the arc in the post early miocene the lower to middle miocene misaki group is a 3 000 m thick siliciclastic forearc basin fill consisting of wave dominated shallow marine and overlying braid plain deposits its defining features are the low ichnodiversity and paucity of ichnofabrics for instance up to 96 of the total thickness of the measured offshore deposits are non or very slightly bioturbated despite the other normal offshore deposits are generally highly bioturbated although the less bioturbated sediments were previously considered as anoxic deposits anoxic water was unlikely to develop within the highly open wave dominated shallow marine settings the highly active tectonics associated with the spreading of the two backarc basins and the forced subduction most likely caused sediment mass production in the hinterland as evidenced by the sedimentological features of the coeval kuma group and over sedimentation highly frequent and rapid sedimentation that was taken place across the entire misaki basin this over sedimentation supported by a series of evidence such as the pervasive soft sediment deformation across the group estimated rate of net aggradation more than 136 to 230 cm kyr etc most likely induced the colonisation of depauperated fauna and diluted their ichnofabrics across the entire basin the extremely active tectono sedimentation played an important role in the development of the basin wide anomalous benthic ecosystems and ichnofabrics during the early to middle miocene

use of an integrated finite discrete element method discrete fracture network approach to characterize surface subsidence associated with sub level caving abstract the lkab kiruna sub level cave mine located in kiruna sweden is one of the most well studied sub level cave mines due to proximity of the city to the hanging wall the mine has developed a comprehensive surface deformation monitoring program which is perhaps unparalleled in the mining industry this surface monitoring scheme provides an excellent data source with which to constrain numerical modelling in this study a finite discrete element modelling approach coupled with a discrete fracture network fdem dfn is utilized to analyse the kiruna hanging wall surface subsidence with an emphasis on investigating the influence of discontinuity persistence and spacing the fdem dfn data interpretation uses a variety of novel approaches including time displacement hanging wall deformation characterization numerical inverse velocity analysis and virtual hanging wall inclinometer simulation to improve our understanding of the extent and mechanism of hanging wall failure with mine advance the simulated displacements correspond closely to the actual field data illustrating the ability of the proposed approach to reproduce sub level cave behaviour three distinct time displacement phases namely regressive progressive and steady state are observed in the fdem dfn models the paper also reviews the potential application of the inverse velocity method and virtual inclinometers in characterizing sub surface brittle failure associated with sub level caving

a pleistocene landslide dammed lake jinsha river yunnan china on both sides of the jinsha river valley near benzilan deqen northwest of yunnan china a series of varied lacustrine deposits have been discovered under the fourth terrace q 3 2 landslide debris has been identified underlying the lacustrine deposits indicating that the lacustrine deposits were caused by a landslide damming the jinsha river u series dating shows that the age of the upper and middle portions of the lacustrine deposits on the right bank were 55 4 3 5 and 82 1 6 6 ka respectively lacustrine deposits on the left bank have been dated to 122 0 12 4 ka at the bottom which indicates that the large scale landslide was formed before 122 0 12 4 ka and the paleo lake was developed within the early stage to the mid stage of the late pleistocene the characteristic of spore pollen and high content of caco 3 in the lacustrine clays reveal that the paleoclimate was semi arid with less heavy rainfall considering the regional neotectonic background the authors prefer to interpret that the benzilan ancient landslide dammed lake was caused by an ancient earthquake the discovery of the ancient landslide dammed lake provides significance to the understanding of the formation and evolvement of calamitous geological hazards along large rivers c 2010 elsevier ltd and inqua all rights reserved

the relationship between seismic deformation and deep seated gravitational movements during the 1997 umbria marche central italy earthquakes abstract this paper re evaluates the origin of some peculiar patterns of ground deformation in the central apennines observed by space geodetic techniques during the two earthquakes of the colfiorito seismic sequence on september 26th 1997 the surface displacement field due to the fault dislocation as modelled with the classic okada elastic formulations shows some areas with high residuals which cannot be attributed to non simulated model complexities the residuals were investigated using geomorphological analysis recognising the geologic evidence of deep seated gravitational slope deformations dsgsd of the block slide type the shape and direction of the co seismic ground displacement observed in these areas are correlated with the expected pattern of movement produced by the reactivation of the identified dsgsd at least a few centimetres of negative line of sight ground displacement was determined for the costa picchio mt pennino and mt prefoglio areas a considerable horizontal component of movement in the costa picchio dsgsd is evident from a qualitative analysis of ascending and descending interferograms the timing of the geodetic data indicates that the ground movement occurred during the seismic shaking and that it did not progress appreciably during the following months this work has verified the seismic triggering of dsgsd previously hypothesized by many researchers a further implication is that in the assessment of dsgsd hazard seismic input needs to be considered as an important cause of accelerated deformation

cool water shell bed taphofacies from miocene pliocene shelf sequences in new zealand utility of taphofacies in sequence stratigraphic analysis

deep seated gravitational slope deformation large scale rock failure and active normal faulting along mt morrone sulmona basin central italy geomorphological and paleoseismological analyses abstract active faulting is one of the main factors that induce deep seated gravitational slope deformations dgsds in this study we investigate the relationships between the tectonic activity of the nw se normal fault system along mt morrone central apennines italy and the evolution of the associated sackung type dgsd the fault system is considered to be the source of m 6 5 7 earthquakes our investigations have revealed that the dgsd began to affect the mt morrone sw slope after the early pleistocene this was due to the progressive slope instability arising from the onset of the younger western fault with the older eastern fault acting as the preferred sliding zone paleoseismological investigations based on the excavation of slope deposits across gravitational troughs revealed that the dgsd was also responsible for the displacement of late pleistocene holocene sediments accumulated in the sackung troughs moreover we observed that the investigated dgsd can evolve into large scale rock slides therefore as well as active normal faulting the dgsd should be considered as the source of a further geological hazard overall our approach can be successfully applied to other contexts where active normal faults control the inception and evolution of a dgsd

geomorphology and geochronology of sackung features uphill facing scarps in the central spanish pyrenees abstract the paper analyses uphill facing scarps and associated troughs developed in the oversteepened slopes of two neighbouring glacial valleys in the central spanish pyrenees previous studies of sackung landforms in the pyrenees have argued for deglacial unloading as the genetic mechanism but this causal and temporal relationship has not been proved due to the lack of chronological data the antislope scarps in the two studied locations vallibierna and estos are developed in palaeozoic metasedimentary rocks parallel to the contour lines and the structural grain occur in the intermediate sector of the hillslope and are up to 0 5 km long and several meters high a trench was excavated in a sackung trough fill in each of the valleys in order to gain information about their chronology and genesis charcoal from the lowermost unit in vallibierna provided an age of 5 9 cal ka for the sackung and extrapolation of the three dates obtained in estos indicates that the trough formed ca 7 6 7 8 cal ka deglaciation of the studied sectors of the valleys occurred between 16 and 13 ka the time lag of 5 ka suggests that glacial erosion and the subsequent debutressing of the oversteepened valley walls created slopes predisposed to sackung development but did not initiate the movement seismic shaking is proposed as a probable triggering factor this hypothesis although supported by the sudden deformation event recorded by a failure plane exposed in vallibierna trench and by the seismic and neotectonic activity of the area cannot be proved due to the lack of chronological information about paleoearthquakes

quaternary tectonics and large scale gravitational deformations with evidence of rock slide displacements in the central apennines central italy eight cases of large scale gravitational movements with evidence of rock slide type displacements evolving close to quaternary faults have been analysed in the central apennines geomorphological and structural surveys have defined the relationship between the gravitational displacements and the tectonically controlled modifications of the landscape the evolution of all the investigated cases has been conditioned by the presence of fault planes located along the mountain slopes in most cases mt cefalone cima della fossa villavallelonga casali d aschi gioia dei marsi the faults played or are playing a primary role in increasing the local relief and their activity represents the main geomorphic factor conditioning the gravitational movements this kind of relationship has been observed along mountain slopes bordering depressions which have not been drained for most of their geomorphic history or have been characterised by an evolution of the hydrographic network that has been conditioned only by the local tectonic subsidence in such cases the gravitational movements develop in the footwalls of the faults in other cases fiamignano pescasseroli the faults have played a passive role since they only bound the sliding masses and coincide with the surficial expressions of the sliding planes therefore the gravitational displacements develop in the hangingwall of the faults the evolution is conditioned by the incision of the hydrographic network in response to regional quaternary uplift the illustrated case studies provide a wide range of examples of the gravitational response of slopes to the modifications of the landscape due to linear and areal tectonics the identification of the geomorphic traces of the large scale gravitational movements along fault controlled mountain fronts has implications for hazard particularly for the evolution of the displacement the quantitative analysis of the vertical displacements and data on the characteristics of the surface breaking during historical earthquakes demonstrate that along fault offsets strongly increases where the unstable large scale rock masses are located therefore the large coseismic vertical offset may represent a major problem for the displacement of utilities and may represent a potential cause for the sudden and catastrophic evolution of the gravitational movement

the presence of tawera gayi hupe in gay 1854 veneridae bivalvia in southern south america did tawera achieve a late cenozoic circumpolar traverse cenozoic tawera marwick 1927 from the southern hemisphere exhibits a pattern of disjunt distribution around the southern oceans a single species tawera gayi hupe in gay c 1854 historia fisica y politica de chile zoologia 8 paris is confined to southern south america taking into account the occurrence of tawera in the fossil record taxonomy based on shell morphology and available information on extant species of tawera it is plausible that the genus appeared first in southern australia during the early miocene and then expanded and radiated to new zealand it also appears that tawera first crossed from australasia to south america during the early pleistocene this picture can be better explained if tawera was able to achieve circumglobal range by means of the antarctic circumpolar current thus different potential factors of dispersal i e larval dispersal drifting kelp rafting and pleistocene cooling are considered and discussed shell morphology and overall appearance of tawera gayi is very similar to tawera philomela smith 1885 from south africa and tawera mawsoni hedley 1916 from macquarie island suggesting these taxa have a close relationship one postulated explanation which should be confirmed by means of a phylogenetic study is a subsequent migration of tawera from south america arriving first to the southern african region via the west wind drift islands province and then probably coming back again to australasia it could have been mediated via the same current during the late pleistocene and much later during the holocene

insights on the kinematics of deep seated gravitational slope deformations along the 1915 avezzano earthquake fault central italy from time series dinsar abstract among the causes of deep seated gravitational slope deformations dgsd the most important is relief energy which is closely related to the intensity of the active tectonic deformations either at the regional scale or at the scale of a single active fault we analyzed some examples of dgsd from the eastern border of the fucino basin in the central apennines where extensional tectonics has been active since the late pliocene photogeological and field geomorphological analysis was performed to identify landforms typically associated with dgsd such as counterslope scarps double crests trenches and bulging slopes these features are located on a mountain range at less than 1 km from the causative fault of the 1915 avezzano earthquake we used the sbas differential sar interferometry technique to measure the slow movements of the surface and calculated differential vertical and horizontal ground velocities of 2 4 mm yr 1 during the period spanning from 1992 to 2001 the quantitative information on the kinematics of the deformation provided some inferences on the different processes responsible for the evolution of the observed dgsd the displacement time series shows non linear deformation trends at some locations possibly correlated with a strong meteorological event we speculate that dgsd in this area are normally subject to slow deformation and that sudden slip along sliding surfaces observed in excavations may sporadically be triggered off by extreme meteorological or seismic events evidence of catastrophic collapse of previous dgsd along the same mountain slope reinforce this hypothesis

influence of structural framework on mountain slope deformation in the maiella anticline central apennines italy abstract relationships between tectonic framework and gravity driven phenomena have been investigated in an area of the central apennines italy characterised by high relief the north south half dome shaped maiella anticline lies in the easternmost part of the apennine fold and thrust belt its backlimb is bordered by the caramanico fault a normal fault with a maximum downthrown of about 3 5 km that separates the western slope of the maiella massif from the caramanico valley the southwestern maiella area is affected by deep seated gravitational slope deformation indicated by major double crest lines down hill and up hill facing scarps a pattern of crossing trenches bulging at the base of slopes and the presence of different types of landslide and talus slope deposits the onset and development of deep seated gravitational slope deformations and the location of quaternary massive rockslope failures have been strongly influenced by the structural framework and tectonic pattern of the anticline deep seated gravitational slope deformation at mt macellaro mt amaro ridge has developed along the maiella western reverse slope in correspondence with the anticline axial culmination it is bordered at the rear by a nnw sse oriented dextral strike slip fault zone and has an e w direction of rock mass deformation closer to the southern plunging area of the anticline gravity driven phenomena show instead a n s and nw se direction influenced by bedding attitude 3d topographic models illustrate the relationship between deep seated gravitational slope deformation and massive rockslope failures the campo di giove rock avalanche a huge quaternary failure event was the result of an instantaneous collapse on a mountaine slope affected by a long term gravity driven deformation

reconstructing the geochronological evolution of large landslides by means of the trenching technique in the yesa reservoir spanish pyrenees abstract detailed geomorphological mapping has revealed that the slopes upstream of the yesa dam are affected by several flysch landslides the largest landslides correspond to la refaya rotational slide 11 million m3 situated just upstream of the spillway and el vertedero translational slide 6 million m3 located 1 5 km upstream of the dam a portion of el vertedero landslide 3 million m3 was reactivated in 2006 due to overloading caused by an earth heap a higher earth dam will be built on the downstream side of the existing gravity concrete dam to raise the maximum water level of the reservoir by 23 m the retrodeformation analysis of the deposits exposed in two trenches excavated in the upper part of these landslides together with the obtained absolute ages c14 and osl have provided information on the kinematics and evolution of these slope movements the main findings derived from the 45 m long trench dug in the closed depression developed at the foot of the head scarp of la refaya landslide include 1 the landslide is older than 12 ka and has undergone a cumulative rotation higher than 17 yielding a mean rotation rate of about 1 4 millennium 2 most of the rotation 14 occurred before 5 8 ka and according to the trench stratigraphy the kinematics of the landslide has been dominated by progressive displacement no evidence of catastrophic reactivation has been found the 45 m long trench excavated across the scarp and bench situated at the head of the non reactivated portion of el vertedero translational slide reveals that 1 the landslide is older than 38 ka 2 the trenched portion has undergone at least one reactivation subsequent to 20 ka and has remained inactive for a long time as suggested by the highly degraded bedrock scarp with a slope of 18 compared to the 60 dip of the underlying failure plane based on this study corrective measures with an estimated cost of 11 5 million euros have been designed for this slope the investigation illustrates the usefulness and cost effectiveness of the trenching technique allied with geochronological methods to obtain information on the precise limits age failure mechanism kinematics progressive vs episodic displacement movement rate and chronological evolution of landslides

gis application for regional assessment of seismically induced slope failures in the sierra nevada range south spain along the padul fault complete rupture of the padul fault represents one of the largest plausible earthquakes in the sierra nevada range one of the most seismically active regions of spain we performed a regional assessment of earthquake triggered slope instabilities in the western part of the range to determine the most likely types of failures from such an earthquake in the region and suggest where such failures have a higher likelihood of occurring these results are broadly useful for management of regional life lines and future development first a slope instability inventory of the sierra nevada was produced to identify the most common instability types subsequently the newmark s sliding rigid block methodology implemented in a geographic information system was used to obtain the distribution of newmark displacements in the area considering a mw 6 6 earthquake on the padul fault the newmark displacements were then compared to the distribution of the inventoried slope instabilities to identify the areas where seismicity could reactivate old slope instabilities or generate new ones and to identify the involved landslide typology the most likely seismically induced slope instabilities in the sierra nevada are rock falls and rock slides these types of instabilities could be triggered by newmark displacements of 2 cm or less

deep seated gravitational slope deformations along the active bocono fault in the central portion of the merida andes western venezuela abstract two very large deep seated gravitational slope deformations in the highlands of the merida andes venezuela are herein described the mucubaji pass and cerro la camacha these slope movements have slid in post last glacial maximum times in addition both landslides are in very close association with the active bocono fault trace the cerro la camacha camacha range landslide is fault bounded along its northwest flank whereas the mucubaji pass mass movement is even cut by the active fault trace the almost 10 km long mucubaji slide mobilizes lgm moraine deposits along the unconformable basement contact la camacha slope movement is a sackung type landslide involving two huge masses that affect the entire northwestern slope of the la camacha range this sackung is at least 20 km long paralleling the active bocono fault trace combination of high relief energy gravitational forces and seismic shaking related to an on site active fault could be responsible for the destabilization of the slopes or massif in both cases although the seismically induced re activation of the la camacha landslide is very likely there is no proof for that yet conversely the mucubaji slide shows geomorphic geodetic and sedimentary evidence of episodic activity in recent times which could be ascribed to seismic triggering in the particular case of the la camacha sackung the combination of dextral slip along the bocono fault and a se dipping fault plane could additionally favor the destabilization of the nw slope of the la camacha range

the evolution of the samaoding paleolandslide river blocking event at the upstream reaches of the jinsha river tibetan plateau abstract a large number of landslides have occurred in the upstream reaches of the jinsha river tibetan plateau due to the intensity of tectonic movement in the area remote sensing and field investigation indicate that one of them the samaoding paleolandslide previously blocked the river various river blocking phenomena are well preserved including the old landslide dam and deposits fluvial sediments and hydrostatic sandy sediment to better understand the evolution of the samaoding landslide the authors carried out thermoluminescence tl dating and numerical simulations the tl analysis shows that the landslide occurred at 10 6 0 5 ka bp discrete element method dem simulation of the landslide based on landform restoration provided results that are consistent with field observations the simulation indicates that the entire landslide process lasted for 80 s and the sliding mass reached a maximum velocity of 64 m s the landslide formed a landslide dam with a length of 1900 m a width of 600 m and a depth of 200 m the simulation results show that the level of the riverbed at that the time of the landslide was at least 25 m higher than it is today on the combined basis of the simulation results and field observations the authors propose explanation that the following valley evolution sequence occurred after river blocking the landslide dam experienced flood overtopping and then was eroded until it had mostly had been transported away by river flow and the river then rapidly incised the bedrock to form the present day landform based on the field investigations the authors summarize the failure mechanism of steep inclined antidip rockslides and found that tectonics play an important role in the formation of landslide dams or trigger of landslides and the failure of landslide dams in an active tectonic environment of tibetan plateau

twenty years of paleoseismology in italy abstract italy has one of the most complete and historically extensive seismic catalogues in the world due to a unique and uninterrupted flow of written sources that have narrated its seismic history since about the end of the iron age seismic hazard studies have therefore always been mainly based upon this huge mass of data nevertheless the italian catalogue probably lacks many m 6 5 events the seismogenetic structures responsible for which are characterized by recurrence times that are longer than the time span covered by our historical sources for these reasons and as in other countries earthquake data that in italy have been derived from paleoseismological studies should finally become a necessary ingredient in seismic risk assessment indeed over the past 20 years some hundred trenches have been excavated supplying reliable and conclusive data on the recent activities of many faults through to many robust datings of surface fault events these studies have provided the ages of several unknown or poorly known m 6 5 earthquakes here we summarize the state of the art of paleoseismology in italy and present a first catalogue of 56 paleoearthquakes pci that occurred mainly in the past 6 kyr the pci integrates the historical instrumental seismic catalogue and extends it beyond the recurrence time of the seismogenetic faults 2000 1000 yr we feel confident that the use of the pci will enhance future probabilistic seismic hazard assessment and thus contribute to more reliable seismic risk mitigation programs

predicting of land surface uplift caused by the flooding of underground coal mines a case study abstract the liquidation of underground mines as in flooding of mining excavations and goafs often leads to movements of the rock mass and land surface as a result of pressure changes in the flooded zones the changes resulting from the rising water table caused by the changes in the stress and strain state as well as the physical and mechanical properties of rock layers can lead to damage to surface construction objects and environmental changes such as chemical pollution of the surface water this is why the ability to predict the movements of rock masses generated as a result of mine closure by flooding serves a key function in relation to the protection of the land surface and buildings present thereon currently the world literature presenting methods of forecasting ground surface uplift during mine flooding is very modest and is limited to three analytical methods pottgens fenk s and sroka s method however the numerical methods used in this subject area are limited only to modeling the phenomenon using the back analysis method and are not used for forecasting the author s methodology based on the finite element method presented in the article allows on after calibrating the 3d numerical model using surface subsidence measurements as well as geological and mining data to simulate the flooding process by changing the density of the medium according to classical soil and rock mechanics principles and then obtain prognostic values for ground surface uplift this methodology has been used in the example of a german underground coal mine which has been flooded in 1999 the authors have built a 3d numerical model and then performed simulations the results of calculations were compared with the results of measurements obtaining compliance at the level of 5

earthquake supercycles in central italy inferred from 36cl exposure dating we use 36cl surface exposure dating to determine the slip release pattern over the last 15 kyr for the velino magnola fault a major active normal fault in central italy we sampled the fault at five well separated sites along its length and modeled the 36cl concentrations measured in the 376 samples we find that the fault broke in at least 9 large earthquakes that occurred in two 5 6 ka long supercycles each cycle included a 4 5 ka long phase of relative quiescence followed by a cluster of at least 3 large earthquakes or earthquake sequences that released most of the accumulated strain in 1 ka all 9 identified events broke the entire fault and produced maximum surface slips of 2 3 m though the velino magnola fault seems presently in a stage of relative quiescence it may re enter a phase of paroxysmal seismic activity in a few hundred of years

tibetan plateau river incision inhibited by glacial stabilization of the tsangpo gorge much attention has focused on how and when the tibetan plateau formed but far less research has been done on the controls on river incision into the plateau itself oliver korup and david montgomery address this issue which also relates to the question of why the tibetan plateau is still there at all despite hosting one of the deepest gorges on earth the plateau edge is extremely well defined and according to widely accepted stream power theory should be heavily dissected by one of asia s most powerful rivers the yarlung tsangp or yarlung zangbo korup and montgomery propose that the southeastern edge of the plateau was preserved in part by the presence of glaciers that were large enough during the holocene to stall aggressive river downcutting along the plateau margin a considerable amount of research has focused on how and when the tibetan plateau formed in the wake of tectonic convergence between india and asia1 although far less enquiry has addressed the controls on river incision into the plateau itself2 widely accepted theory3 predicts that steep fluvial knick points river reaches with very steep gradients in the eastern himalayan syntaxis at the southeastern plateau margin should erode rapidly4 driving a wave of incision back into the plateau preservation of the plateau edge thus presents something of a conundrum that may be resolved by invoking either differential rock uplift matching erosional decay5 6 7 or other mechanisms for retarding bedrock river incision8 9 in this region where high stream power excludes the potential for aridity as a simple limit to dissection of the plateau10 here we report morphologic evidence showing that quaternary depression of the regional equilibrium line altitude where long term glacier mass gain equals mass loss was sufficient to repeatedly form moraine dams on major rivers such damming substantially impeded river incision into the southeastern edge of the tibetan plateau through the coupled effects of upstream impoundment and interglacial aggradation such glacial stabilization of the resulting highly focused river incision centred on the tsangpo gorge could further contribute to initiating and accentuating a locus of rapid exhumation known as tectonic anaeurysm6

mass movement in the himalaya new insights and research directions abstract ongoing studies that relate tectonics to the processes at the surface of earth show that many more sources of information about agents of shallow denudation such as mass movement are required to comprehend the long term erosion that leads to deep denudation over geologic time mass movement in the himalaya is scale dependent from the massive extension of whole mountain ranges gravity tectonics through the sackung failure of single peaks to the smallest slope failures generally denudation of the himalayan orogen begins with slope failure onto glaciers and into river valleys and continues by glacial and fluvial transport the maximum size of stable slopes and mean angles of slope that are produced by these failures are complex and controlled by a variety of factors including mass strength of the rocks stress fields angles of internal friction controlled by rock type cohesion that includes the control of rock temperature bulk unit weight of rock and discontinuities the processes of mass movement in the himalaya have been described many times for the past two centuries recently developments in a variety of fields have been introduced to assess the character of mass movement geomorphometry remote sensing digital elevation models and geographic information system technology are revolutionizing the study of mass movement in the himalaya

background seismicity in the central apennines of italy the abruzzo region case study abstract we investigate background seismic activity of the abruzzo region a 5000 km2 area located within the central apennines of italy where in the past 600 years at least 5 large earthquakes i xi x have occurred between april 2003 and september 2004 a dense temporary seismic network composed of 30 digital three component seismic stations recorded 850 earthquakes with 0 9 the seismicity occurs at a low and constant rate of 2 6 e 04 events day km2 and is sparsely distributed within the first 15 km of the crust minor increases in the seismicity rate are related to the occurrence of small and localised seismic sequences that occur at the tip of major active normal faults along secondary structures we observe that during the 16 months of study period the fucino fault system responsible for the 1915 fucino earthquake ms 7 0 and the major normal faults of the area did not produce significant seismic activity fault plane solutions evaluated using p wave polarity data show the predominance of normal faulting mechanisms 55 with ne trending direction of extension coherent with the regional stress field active in this sector of the apennines around 27 of the focal solutions have pure strike slip mechanisms and the rest shows transtensional faulting mechanisms that mainly characterise the kinematics of the secondary structures activated by the small sequences we hypothesize that the largest known nw trending normal faults are presently locked and we propose that in the case of activation the secondary structures located at their tips may act as transfer faults accommodating a minor part of the extensional deformation with strike slip motion

a methodology based on strain analysis for identifying potential discontinuous deformation zones in sublevel caving mines abstract underground mining operations using the sublevel caving method often result in discontinuous ground deformations involving surface cracks determining the limit of the discontinuous deformation zone is important for the relocation of neighbouring residential areas mining infrastructure and the planning of underground mining operations the limit of the discontinuous deformation zone is characterised by the outermost surface crack which is a tensile crack when it occurs and is correlated with the horizontal ground tensile strain in this study a mathematical procedure combining the horizontal displacement as periodically monitored by total station and gps multiquadric radial basis function mq rbf interpolation and continuum mechanics is provided to calculate the strain state at any point on the ground then the relationship between a new tensile crack and horizontal ground tensile strain is studied to determine the criterion representing the presence of a new tensile crack this means that when the criterion at any point on the ground is satisfied the point will have the potential to crack based on this the potential discontinuous deformation zone where surface cracks may occur can be identified potential break angles at representative sections can then be determined a case study is presented to illustrate the results given by the above methodology the result shows that when major principal horizontal ground strain e1 at any point on the ground reaches the potential cracking major principal strain pcmps 6 mm m in this case study the point will have the potential to crack subsequently the area within the outermost contour of the pcmps can be defined as the potential discontinuous deformation zone moreover the approximate matching of the limits of potential discontinuous deformation zones and surface cracks verifies the reliability of the mathematical procedure and the rationality of the pcmps in identifying the discontinuous deformation zone additionally in this case study the potential break angles at two respective sections are significantly different indicating that the break angles should be further studied and care taken in design of works in these two zones respectively

geomorphic signatures of recent normal fault activity versus geological evidence of inactivity case studies from the central apennines italy abstract we have here analysed two normal faults of the central apennines one that affects the south western slopes of the montagna dei fiori montagna di campli relief and the other that is located along the south western border of the leonessa intermontane depression through this analysis we aim to better understand the reliability of geomorphic features such as the fresh exposure of fault planes along bedrock scarps as certain evidence of active faulting in the apennines and to define the quaternary kinematic history of these tectonic structures the experience gathered from these two case studies suggests that the so called geomorphic signature of recent fault activity must be supported by wider geomorphologic and geologic investigations such as the identification of displaced deposits and landforms not older than the late pleistocene and or an accurate definition of the slope instabilities our observations indicate that the fault planes studied are exposed exclusively because of the occurrence of non tectonic processes i e differential erosion and gravitational phenomena that have affected the portions of the slopes that are located in the hanging wall sectors the geological evidence we have collected indicates that the montagna dei fiori montagna di campli fault was probably not active during the whole of the quaternary while the tectonic activity of the leonessa fault ceased or strongly reduced at least during the late pleistocene and probably since the middle pleistocene the present lack of activity of these tectonic structures suggests that the fault activation for high magnitude earthquakes that produce surface faulting is improbable i e m 5 5 6 0 with reference to the apennines according to michetti et al michetti a m brunamonte f serva l vittori e 1996 trench investigations of the 1915 fucino earthquake fault scarps abruzzo central italy geological evidence of large historical events j geoph res 101 5921 5936 michetti a m ferreli l esposito e porfido s blumetti a m vittori e serva l roberts g p 2000 ground effects during the september 9 1998 mw 5 6 lauria earthquake and the seismic potential of the aseismic pollino region in southern italy seis res letts 71 31 46 if according to the current view the shifting of the intra apennine extension towards the adriatic sectors is still active the montagna dei fiori montagna di campli fault might be involved in active extensional deformation in the future

sedimentary evidence of outburst deposits induced by the diexi paleolandslide dammed lake of the upper minjiang river in china abstract this study reveals that a distinct damming incident occurred during a prehistory period approximately 30 ka bp in the upper minjiang river at the southeastern margin of the tibetan plateau which formed a giant dammed lake it can be inferred that paleoseismic induced major landslides were the direct cause of the river damming the dammed lake breached and caused a large outburst flood at about 27 ka bp between the section of the prehistoric ancient dam body and its downstream areas 5 km an abundance of diamicts consisting of a poor sorted wide range of particle sizes including gravel sand and minor silt and clay have been observed the outburst deposits in the diexi area maybe divided into two periods the thick outburst deposits represented the earlier and largest dammed break event and the deposit terrace was due to the subsequent and smaller dammed break event the sedimentary structures of the outburst deposits included imbrication cavitation matrix and massive structures as well as gravel support stacked structures furthermore a special sedimentary structure became evident consisting of a rhythmite interbedded structure composed of a coarser gravel layer and a finer sand and gravel layer with no sand lens formed within the layers this special structure can potentially provide an important original criterion for the outburst deposits in this area the two types of facies associations have been recorded which indicate contrasting sediment transport regimes the characteristics of boulder facies were most likely associated with hyperconcentrated flood flows however the finer grained gm gfm grm facies which overlaid the bcm facies were determined to represent the waning stage of the flooding events the delicate structures as well as the absence of coarse components in the sh facies indicated an episode of accumulations which was subsequent to the deposition of the underlying bcm facies the results of this study potentially provide important implications for the interpretation of the diamicts in the diexi area the grain size frequency curves of the outburst deposits in the diexi area were found to all be bimodal a main peak and an inconspicuous sub peak these findings indicated a poorly sorted sedimentary structure it was found that from the upstream segment to the downstream segment the gravel sediment became gradually lessened while the fine grained sediment increased additionally the outburst flood hydrodynamic intensity was found to have gradually become weakened

spatial and temporal variations in growth rates along active normal fault systems an example from the lazio abruzzo apennines central italy abstract the geometry kinematics and rates of active extension in lazio abruzzo italian apennines have been measured in order to gain a better understanding of the spatial and temporal variations in fault growth rates and seismic hazards associated with active normal fault systems we present fault map traces throws throw rates and slip directions for 17 parallel en echelon or end on active normal faults whose 20 40 km lengths combine to form a soft linked fault array ca 155 km in length and ca 55 km across strike throw rates derived from observations of faulted late glacial features and holocene soils show that both maximum throw rates and throw rate gradients are greater on centrally located faults along the strike of the array total throws and throw gradients show similar spatial variations but with weaker relationships with distance along strike when summed across strike throw rates are increasingly high towards the centre of the array relative to summed throws we interpret the above to suggest that throw rates have changed in the recent past ca 0 7 ma from spatially random fault growth rates initiating at 2 5 3 3 ma to growth rates that are greater on centrally located faults we interpret this as evidence for fault interaction producing throw rate variations that drive throw profile readjustment on these crustal scale soft linked faults the results are used to discuss seismic hazards in the region which are quantified in a second paper in this issue