upper miocene to lower pliocene sigaboy formation turbidites on the pujada peninsula mindanao philippines internal structures composition depositional elements and reservoir characteristics abstract turbidites of the upper miocene to lower pliocene sigaboy formation on the pujada peninsula southeastern mindanao philippines potentially provide a superb record how a forearc basin may fill up investigation of the basin sequences allows the provenance of the material to be established and hence the data are useful for tectonic models of the sub region in addition information obtained from the basin may give insights that are useful for petroleum exploration which mindanao is an important area the sigaboy formation is exposed for 45 km along the western coast of pujada peninsula the unit directly overlies various levels within the pujada ophiolite various facies within the formation identified from the detailed stratigraphic logs of six major outcrops represent channelized and unchannelized deposits of submarine fans that were deposited largely by turbidity currents field and petrographic evidence suggest that the portions of the sangihe arc and its uplifted outer arc ridge now forming the pujada peninsula provided the main source of detritus that was shed into the forearc basin this event probably followed the initial subduction of the snellius plateau halmahera arc in mindanao latest middle miocene and prior to the initiation of the philippine trench in the region

regional gps data confirm high strain accumulation prior to the 2000 june 4 mw 7 8 earthquake at southeast sumatra summary site velocities derived from repeated measurements in a regional gps network in southeast asia help to constrain the motion of tectonic blocks as well as slip rates along major faults in the area using 3 d forward dislocation modelling the influence of seismic elastic loading and unloading on the measured site motions are approximated results suggest that the northwestern sunda arc is fully coupled seismogenically whereas its eastern part along java shows localized deformation higher horizontal velocity gradients than expected from the modelling of a fully coupled plate interface west of manila in the philippines suggest that deformation may be localized there assuming that geodetically derived convergence represents long term rates accumulated geodetic moments are compared to those derived using seismic data from 1977 to 2000 harvard cmt catalogue if areas displaying localized deformation are dominated by creep processes the largest difference between accumulated and seismically released deformation is located where the 2000 june 4 mw 7 8 sumatra earthquake occurred

an induced seismicity experiment across a creeping segment of the philippine fault the location of seismicity induced by forced fluid flow provides information about domains of pore pressure variation while changes in fluid content are identified through changes in seismic velocity these effects have been investigated in the geothermal field of rrongona n which lies on a creeping portion of the philippine falllt on levte island t ocally the left lateral strike slip philippine fa ult branches out into three subparallel segments eastern central and western fault lines in june jnly 1997 a water stinlulation was undertaken in a well that intersects the central f ault line l980 m below grour tl surface 36 000 m3 were iriject ed between the casing shoe at 1308 m and the well bottom at 2177 m the seismicity was monitored with a surface station nctwork of 18 sta iions more than 400 events induced by the injection cxpcrimcrlt as well as by r outine injections associated with the gcothcrrnal field exploitation were recnrded in the vicinity of the well they have been located througlr 3 sim llt aneol s t hr e dimensior d 3 d velocity hypocent er invervior procedure none of the microearthquakes are locateti along the central fault line they all occurred below the casing shoe to the east of thr farllt line i e within thc gcothcrmal reservoir and m ostly below thr bottom of the well results from the injcct ion experiment and the 18 rnonths of seismic monitoring along thc c erlt ral and west fa uit lirics suggest an aseismic behavior of this major continental fa llt at this localion the 3 d velocily n odel determirled lrorr thc lravel lirrle ir versioll fur seismic erents observed during iruecliu s is cun pared lo lhat ub1ai11t d rrom seismic monitoring conducted prior to any injection activities an increase of p wave velocity is observed during the water injection this vclocitj irlcrease is localized a ilhin the seisrr icily cloud and is interpreted as an increase in liquid content within the initial liquid vapor multiphase part of the reservoir 3philipplne yalional oil c e l cor duct ed l r ross

challenges and recommendations in mapping of glacier parameters from space results of the 2008 global land ice measurements from space glims workshop boulder colorado usa on 16 18 june 2008 the us national snow and ice data center held a glims workshop in boulder co usa focusing on formulating procedures and best practices for operational glacier mapping using satellite imagery despite the progress made in recent years there still remain many cases where automatic delineation of glacier boundaries in satellite imagery is difficult error prone or time consuming this workshop identified six themes for consideration by focus groups 1 mapping clean ice and lakes 2 mapping ice divides 3 mapping debris covered glaciers 4 assessing changes in glacier area and elevation through comparisons with older data 5 digital elevation model dem generation from satellite stereo pairs and 6 accuracy and error analysis talks presented examples and work in progress for each of these topics and focus groups worked on compiling a summary of available algorithms and procedures to address and avoid identified hurdles special emphasis was given to establishing standard protocols for glacier delineation and analysis creating illustrated tutorials and providing source code for available methods this paper summarizes the major results of the 2008 glims workshop with an emphasis on definitions methods and recommendations for satellite data processing while the list of proposed methods and recommendations is not comprehensive and is still a work in progress our goal here is to provide a starting point for the glims regional centers as well as for the wider glaciological community in terms of documentation on possible pitfalls along with potential solutions

transcurrent movements in the burma andaman sea region the drag produced by the northward movement of the indian plate has caused the indoburman ranges an accretionary prism to decouple from the burma plate along the kabaw fault and the burma plate itself has decoupled from the eastern highlands of burma along the sagaing fault the indoburman ranges have probably been dragged north slightly ahead of the burma plate although at times the two plates may have locked together to move as one unit it is suggested that the double arc formed by the indoburman ranges and the andaman nicobar sumatra islands was formerly one large single arc northward translation of this larger single arcuate structure has caused the tail end of the arc i e the andaman nicobar sumatra section to rotate into the burma plate causing a bending of the arc to form the present double arc and compression within the burma plate to form the pegu yoma folding northward movement of the burma plate has also resulted in offset by over 400 km of the irrawaddy river from its former connection through the channel of what is now the chindwin river

the interaction between volcanoes and strike slip transtensional and transpressional fault zones analogue models and natural examples regional strike slip faulting can control magma movements deform volcanoes and may destabilise their flanks the aim of this study is to address this problem by comparing two natural examples basse terre island volcanoes lesser antilles and maderas volcano nicaragua with analogue experiments the field and remote sensing analyses of their structures reveal that guadeloupe volcanoes which developed in a1 45 striking sinistral transtensional fault zone are dominantly fractured in a 090 e120 direction which is parallel to the maximum principal horizontal stress and to the elongation direction of the summit graben of analogue models this graben is bordered by the sigmoid i fault or y shear structure and has facilitated the formation of the beaugendre and vieux habitants valleys by faulting erosion or collapse this structure has also influenced the injection of dykes and the transport of hydrothermal fluids the comparison of maderas volcano with the analogue models confirms that the volcano has developed parallel to a 135

coseismic displacement of the 5 april 2017 mashhad earthquake mw 6 1 in ne iran through sentinel 1a tops data new implications for the strain partitioning in the southern binalud mountains abstract the outward expansion of the northeastern iranian plateau is mainly accommodated by a series of widely distributed range normal thrust and range parallel strike slip faults however the role of the strike slip faults in this region s strain partitioning kinematics remains unclear the occurrence of the 5 april 2017 mw 6 1 mashhad earthquake provides us a rare opportunity to study this topic because this earthquake struck the southern binalud mountains which are experiencing an oblique convergence between the northward moving lut block and the nw striking binalud and kopeh dagh mountain ranges we process two paired ascending and descending sentinel 1a radar image observations to determine the relative contributions from the dip and strike dip subcomponents in such an oblique collisional domain the interferograms along the line of sight direction and their converted horizontal and vertical displacements indicate that a thrust with a right lateral strike slip fault controlled the rupture process of the mashhad earthquake with the maximum dextral shearing and vertical displacements reaching 19 5 cm and 14 cm respectively coseismic surface deformation measurements are also used to estimate the fault geometry and invert the slip distribution along the underlying seismogenic fault our best fit faulting model suggests that the coseismic rupture occurred on a fault plane with a dip angle of 37 5 and strike angle of 324 the strike slip subcomponent was more significant than the dip slip approaching 95 cm and the dip slip varied from 10 cm to 47 cm the seismic moment release of our preferred fault model is 1 71 1018 nm equivalent to a mw 6 16 earthquake event we also use the preferred fault model to calculate the coulomb failure stress cfs change at the nearby receiver faults combined with an analysis of historical earthquakes and the consistent dextral river deflections along the strike slip fault systems of the southern binalud and kopeh dagh mountains we speculate that the seismogenic structure that triggered the mashhad earthquake should have been one strand fault of the nw se striking kashafrud fault system the strike slip faults in ne iran play an important role in accommodating the lateral transport of crustal material from the convergence front of the lut block and binalud fragments and providing commonly distributed anticlockwise rotation around a vertical axis

plate convergence measured by gps across the sundaland philippine sea plate deformed boundary the philippines and eastern indonesia summary the western boundary of the philippine sea ph plate in the philippines and eastern indonesia corresponds to a wide deformation zone that includes the stretched continental margin of sundaland the philippine mobile belt pmb extending from luzon to the molucca sea and a mosaic of continental blocks around the ph australia sunda triple junction the gps geodyssea data are used to decipher the present kinematics of this complex area in the philippines the overall scheme is quite simple two opposing rotations on either side of the left lateral philippine fault clockwise to the southwest and counterclockwise to the northeast transfer 55 per cent of the ph sundaland convergence from the manila trench to the northwest to the philippine trench to the southeast further south 80 per cent of the ph sunda convergence is absorbed in the double subduction system of the molucca sea and less than 20 per cent along both continental margins of northern borneo finally within the triple junction area between the sundaland ph and australia plates from sulawesi to irian jaya preferential subduction of the celebes sea induces clockwise rotation of the sulu block which is escaping toward the diminishing celebes sea oceanic space from the eastwardadvancing ph plate to the south we identify an undeformed banda block that rotates counterclockwise with respect to australia and clockwise with respect to sundaland the kinematics of this block can be defined and enable us to compute the rates of southward subduction of the banda block within the flores trench and of eastward convergence of the makassar straits with the banda block the analysis made in this paper confirms that this deformation is compatible with the eastward motion of sundaland with respect to eurasia determined by the geodyssea programme but is not compatible with the assumption that sundaland belongs to eurasia as was often assumed prior to this study

measuring ground displacements from sar amplitude images application to the landers earthquake ers sar amplitude images are utilized to map ground displacements from a sub pixel correlation method it yields a ground two dimensional displacement field with independent measurements about every 128m in azimuth and 250m in range the accuracy depends on the characteristics of the images for the landers test case the 1 uncertainty is 0 8m in range and 0 4m in azimuth we show that this measurement provides a map of major surface fault ruptures accurate to better than 1km and information on coseismic deformation comparable to the 92 gps measurements available although less accurate this technique is more robust than sar interferometry and provides complementary information since interferograms are only sensitive to the displacement in range

stability and damping in a dynamical model of hillslope hydrology a stability analysis is performed on the two state variable integral balance model of hillslope hydrology developed by duffy 1996 the motivation for the research is to develop a physically based low dimensional representation of inflow outflow behavior within a hillslope stream setting stability criteria are developed for the model equilibria and are evaluated using the results of numerical solutions of richards equation for a convex concave hillslope geometry we show that for homogeneous hillslopes of three widely varying soil types the single moisture equilibrium is classified as a stable node for low precipitation rates and a stable spiral for wet conditions the spiral equilibrium indicates that the hillslope system is lightly damped and transient oscillations of the state variables are expected for high precipitation rates the timescale of these oscillations is of the order of several days to weeks for the model hillslopes examined furthermore we demonstrate that the model contains a hopf bifurcation from a stable static equilibrium to a stable limit cycle the amplitude phase and frequency of the limit cycle are determined analytically using second order averaging however this behavior is shown to be nonphysical for the particular homogeneous soils and hillslope geometry investigated implications of lightly damped behavior in the hillslope system include moisture oscillations in the field under wet conditions and difficulty in numerical solution of richards equation 1 background the effects of microscale nonlinearity of saturated unsaturated flow on macroscale observable hydrologic behav ior remain largely unknown the highly nonlinear partial dif ferential equation for variably saturated flow richards 1931 indicates the possibility of complex dynamical behavior at the hillslope scale however because energy inputs and especially precipitation are strong and noisy it is difficult to separate the response to such forcing from the dynamics that may be inher ent in the soil groundwater system within the framework of dynamical systems hillslope soil moisture and associated hy drologic fluxes can be thought of as a noisy forced dynamical system consistent with this conceptualization a two state vari able integral balance dynamical model for hillslope hydrology has recently been introduced by duffy 1996 the purpose of this paper is to characterize the dynamical behavior of this model using both analytical methods and the results of numer ical solutions of richards equation in particular we explore conditions for stable and unstable moisture equilibria the approach taken here differs from the local analysis of stability of flow in porous media which is associated with a highly fingered spatial distribution of moisture during infiltra

structure and kinematics of oblique continental convergence in northern fiordland new zealand abstract southeast of the alpine fault in fiordland new zealand late tertiary faults envelope exposures of early cretaceous high p 12 16 kbar granulite facies orthogneisses these exposures allowed us to examine how pre cenozoic structures influenced variations in the degree and style of kinematic partitioning within a zone of oblique continental convergence fault slip data and kinematic modelling show that oblique slip and reverse displacements preferentially were partitioned east of the alpine fault onto curved ne striking surfaces and moderately dipping 30 52 n and nw striking surfaces respectively approximately 3 0 5 5 km of exhumation and 6 5 7 0 km of oblique dextral displacement occurred on faults that display palm tree style geometries and subhorizontal detachments in profile this heterogeneous style contrasts with the near horizontal slip on subvertical surfaces that define the alpine fault north of milford sound the principal axes of instantaneous strain we determined using faults are compatible with principal stress axes derived from earthquakes our data indicate that mechanical anisotropies created by inherited structures controlled the locations and highly variable geometries of faulting since 7 9 ma the effects of these pre existing structures and a focusing of contractional deformation along the northeast margin of fiordland resulted in an unusually high degree of strike slip partitioning across the southernmost onshore segment of the alpine fault

present day crustal deformation along the philippine fault in luzon philippines abstract the philippine fault results from the oblique convergence between the philippine sea plate and the sunda block eurasian plate the fault exhibits left lateral slip and transects the philippine archipelago from the northwest corner of luzon to the southeast end of mindanao for about 1200 km to better understand fault slip behavior along the philippine fault eight gps surveys were conducted from 1996 to 2008 in the luzon region we combine the 12 yr survey mode gps data in the luzon region and continuous gps data in taiwan along with additional 15 international gnss service sites in the asia pacific region and use the gamit globk software to calculate site coordinates we then estimate the site velocity from position time series by linear regression our results show that the horizontal velocities with respect to the sunda block gradually decrease from north to south along the western luzon at rates of 85 49 mm yr in the west northwest direction this feature also implies a southward decrease of convergence rate along the manila trench significant internal deformation is observed near the philippine fault using a two dimensional elastic dislocation model and gps velocities we invert for fault geometries and back slip rates of the philippine fault the results indicate that the back slip rates on the philippine fault increase from north to south with the rates of 22 37 and 40 mm yr respectively on the northern central and southern segments the inferred long term fault slip rates of 24 40 mm yr are very close to back slip rates on locked fault segments suggesting the philippine fault is fully locked the stress tensor inversions from earthquake focal mechanisms indicate a transpressional regime in the luzon area directions of 1 axes and maximum horizontal compressive axes are between 90 and 110 consistent with major tectonic features in the philippines the high angle between 1 axes and the philippine fault in central luzon suggests a weak fault zone possibly associated with fluid pressure

strain partitioning during oblique plate convergence in northern sumatra geodetic and seismologic constraints and numerical modeling global positioning system gps measurements along the subduction zone of northern sumatra 2 s to 3 n reveal that the strain associated with the oblique convergence of the australian plate with eurasia is almost fully partitioned between trench normal contraction within the forearc and trench parallel shear strain within a few tens of kilometers of the sumatran fault kinematic analyses of interplate earthquake slip vectors provide slip rates on the sumatran fault within a few millimeters per year of gps and geologic rates giving us more confidence in the use of slip vectors for inferring slip partitioning elsewhere the inferred slip rate on the sumatran fault is 1 3 less than the full margin parallel component of plate motion an across forearc rotation in the slip vectors suggests that the missing arc parallel shear occurs seaward of the geodetic network between the forearc islands and the trench simple finite element models are used to explore the conditions under which the change in the principal strain rate directions between the forearc and the arc region can occur modeling suggests that neither a preexisting strike slip fault nor a zone of thermally induced lithospheric weakness in the overriding plate is needed for strain partitioning to occur in general forearc slivers form over the region of interplate coupling and are driven along strike by the basal shear a volcanic arc can help the partitioning process by localizing the margin parallel shear strain in the upper plate if its crust and mantle are weaker than its surroundings interplate slip vectors and geodetic results from sumatra together suggest that the highest coupling on the plate boundary occurs beneath and seaward of the forearc islands consistent with inferences about the rupture zones of great nineteenth century earthquakes there the sumatra example suggests that geodetic measurements of interseismic margin parallel shear strain at oblique convergent margins can be used to map the landward extent of the relatively high basal stress beneath the overriding plate if one can correct for strain localization caused by weak upper plate strike slip faults

geology and hazard implications of the maraunot notch in the pinatubo caldera philippines the 1991 pinatubo eruption left 5 6 km3 of debris on the volcano slopes much of which has been mobilized into large lahars in the following rainy seasons also during the eruption collapse localized in part along preexisting faults left a caldera 2 5 km in diameter that almost immediately began to accumulate a 1 6 108 m3 lake by 2001 the water had risen to the fault controlled maraunot notch the lowest northwestern portion of the caldera rim comprising the physiographic sill of the caldera lake that year a narrow artificial canal dug into an old volcanic breccia underlying the outlet channel failed to induce a deliberate lake breakout but discharge from heavy rains in july 2002 rapidly deepened the notch by 23 m releasing an estimated 6 5 107 m3 of lake water that bulked up into lahars with a volume well in excess of 1 6 108 m3 lakes in other volcanoes have experienced multiple breakouts providing practical motivation for this study fieldwork and high resolution digital elevation models reveal andesites and ancient lacustrine deposits strongly fractured and deformed along a segment of the maraunot fault a prominent steeply dipping left lateral fault zone that trends n35 40 w within and parallel to the notch seismicity in 1991 demonstrated that the maraunot fault is still active the fault zone appears to have previously been the erosional locus for a large channel filled with avalanche or landslide deposits of an earlier eruption that were exhumed by the 2002 breakout floods the deformed lacustrine sediments with an uncalibrated 14c age of 14 760 40 year bp from a single charcoal sample attest to the existence of an earlier lake possibly within the tayawan caldera rim remnants of which survive as arcuate escarpments that lake may well have experienced one or more ancient breakouts as well the 2002 event greatly reduced the possibility of another such event by scouring away the erodible breccia leaving less erodible fractured andesites and lacustrine rocks and by enlarging the outlet channel and its discharge capacity several lines of evidence indicate however that future lahar generating lake breakouts at the notch may keep populations of botolan municipality downstream at risk 1 a volume of 9 5 107 m3 of lake water remains perched 0 8 km above sea level 2 seismicity in 1991 demonstrated that the maraunot fault is still active and movements of sufficient magnitude could enlarge the outlet and the discharge through it 3 more likely however with or without earthquake activity landslides from the steep to overhanging channel walls could block the channel again and a major rainstorm could then cause a rise in lake level and sudden breakouts 4 intrusion of a new dome into the bottom of the lake possibly accompanied by phreatic explosions could expel large volumes of lahar generating water

multiple fault slip triggered above the 2016 mw 6 4 meinong earthquake in taiwan rapid shortening in convergent mountain belts is often accommodated by slip on faults at multiple levels in upper crust but no geodetic observation of slip at multiple levels within hours of a moderate earthquake has been shown before here we show clear evidence of fault slip within a shallower thrust at 5 10 km depth in sw taiwan triggered by the 2016 mw 6 4 meinong earthquake at 15 20 km depth we constrain the primary coseismic fault slip with kinematic modeling of seismic and geodetic measurements and constrain the triggered slip and fault geometry using synthetic aperture radar interferometry the shallower thrust coincides with a proposed duplex located in a region of high fluid pressure and high interseismic uplift rate and may be sensitive to stress perturbations our results imply that under tectonic conditions such as high background stress level and high fluid pressure a moderate lower crustal earthquake can trigger faults at shallower depth

the displacement field of the landers earthquake mapped by radar interferometry geodetic data obtained by ground or space based techniques can be used to infer the distribution of slip on a fault that has ruptured in an earthquake although most geodetic techniques require a surveyed network to be in place before the earthquake1 3 satellite images when collected at regular intervals can capture co seismic displacements without advance knowledge of the earthquake s location synthetic aperture radar sar interferometry first introduced4 in 1974 for topographic mapping5 8 can also be used to detect changes in the ground surface by removing the signal from the topography9 10 here we use sar interferometry to capture the movements produced by the 1992 earthquake in landers california11 we construct an interferogram by combining topographic information with sar images obtained by the ers 1 satellite before and after the earthquake the observed changes in range from the ground surface to the satellite agree well with the slip measured in the field with the displacements measured by surveying and with the results of an elastic dislocation model as a geodetic tool the sar interferogram provides a denser spatial sampling 100 m per pixel than surveying methods1 3 and a better precision 3 cm than previous space imaging techniques12 13

coseismic slip deficit of the 2017 mw 6 5 ormoc earthquake that occurred along a creeping segment and geothermal field of the philippine fault abstract coseismic surface deformation imaged through interferometric synthetic aperture radar insar measurements was used to estimate the fault geometry and slip distribution of the 2017 mw 6 5 ormoc earthquake along a creeping segment of the philippine fault on leyte island our best fitting faulting model suggests that the coseismic rupture occurred on a fault plane with high dip angle of 78 5 and strike angle of 325 8 and the estimated maximum fault slip of 2 3 m is located at 6 5 km east northeast of the town of kananga the recognized insignificant slip in the tongonan geothermal field zone implies that the plastic behavior caused by high geothermal gradient underneath the tongonan geothermal field could prevent the coseismic failure in heated rock mass in this zone the predicted coulomb failure stress cfs change shows that a significant positive cfs change occurred along the se segment of central philippine fault with insignificant coseismic slip and infrequent aftershocks which suggests an increasing risk for future seismic hazard

the determination of displacement fields from geodetic data along a strike slip fault observations of angles or distances between stations of a geodetic network are commonly used to infer information about the movement of the surface of the earth the absence of any observations external to the network leads to an ambiguous displacement field existing techniques for eliminating this ambiguity are all unsatisfactory in some respect the best technique an inner coordinate solution is not appropriate for networks located in a strike slip fault environment the inner coordinate solution zeros the rotation of all stations about their center of mass along a strike slip fault like the san andreas however motion normal to the fault is less likely than motion parallel to the fault the solution presented here an outer coordinate solution finds the rotation of the network that minimizes the components of displacement normal to the fault since motion along a strike slip fault is generally expected to be parallel to the fault the displacements obtained with the outer coordinate solution are more reasonable than those obtained with other techniques examination of a trilateration network near san francisco bay demonstrates the large effect that the choice of adjustment technique can have on the inferred relative motion of the two sides of the fault the inner coordinate solution gave a rate of about 1 mm yr whereas the preferred outer coordinate solution rate was 36 mm yr

oblique convergence and slip partitioning in the nw himalaya implications from gps measurements we report gps measurements of crustal deformation across the kashmir himalaya we combined these results with the published results of gps measurements from the karakoram fault system and suggest that in the kashmir himalaya the motion between the southern tibet and india plate is oblique with respect to the structural trend we estimated this almost north south oblique motion to be 17 2 mm yr which is partitioned between dextral motion of 5 2 mm yr on the karakoram fault system and oblique motion of 13 6 1 mm yr with an azimuth of n198 e in the northwest southeast trending kashmir himalayan frontal arc thus the partitioning of the india southern tibet oblique motion is partial in the kashmir himalayan frontal arc however in the neighboring nepal himalaya there is no partitioning the entire india southern tibet motion of 19 20 mm yr is arc normal and is accommodated entirely in the himalayan frontal arc the convergence rate in the kashmir frontal himalaya is about 25 less than that in the nepal himalayan region however here the karakoram fault system accommodates about 20 of the southern tibet and indian plate convergence and marks the northern extent of the nw himalayan arc sliver the kaurik chango rift a north south oriented seismically active cross wedge transtensional fault appears to divide the sliver in two parts causing varying translatory motion on the karakoram fault on either side of the kaurik chango rift

modeling glacier thickness distribution and bed topography over entire mountain ranges with glabtop application of a fast and robust approach 1 the combination of glacier outlines with digital elevation models dems opens new dimensions for research on climate change impacts over entire mountain chains of particular interest is the modeling of glacier thickness distribution where several new approaches were proposed recently the tool applied herein glabtop glacier bed topography is a fast and robust approach to model thickness distribution and bed topography for large glacier samples using a geographic information system gis the method is based on an empirical relation between average basal shear stress and elevation range of individual glaciers calibrated with geometric information from paleoglaciers and validated with radio echo soundings on contemporary glaciers it represents an alternative and independent test possibility for approaches based on mass conservation and flow as an example for using glabtop in entire mountain ranges we here present the modeled ice thickness distribution and bed topography for all swiss glaciers along with a geomorphometric analysis of glacier characteristics and the overdeepenings found in the modeled glacier bed these overdeepenings can be seen as potential sites for future lake formation and are thus highly relevant in connection with hydropower production and natural hazards the thickest ice of the largest glaciers rests on weakly inclined bedrock at comparably low elevations resulting in a limited potential for a terminus retreat to higher elevations the calculated total glacier volume for all swiss glaciers is 75 22 km3 for 1973 and 65 20 km3 in 1999 considering an uncertainty range of 30 these results are in good agreement with estimates from other approaches

detection of creep along the philippine fault first results of geodetic measurements on leyte island central philippine geodetic trilateration gps measurements were acquired from experiments conducted in 1991 and 1993 in the central part of the philippine fault on leyte island displacement vectors deduced from two least squares adjustments indicate a mean slip rate of 26 10 mm yr at an azimuth of about n130 e these values are consistent with the tectonic and kinematic data our results indicate that the displacements are 1 almost parallel to the philippine fault and 2 related to creep along the fault because no moderate seismic events occurred between the two observation epochs

micropaleontology of the 2013 typhoon haiyan overwash sediments from the leyte gulf philippines abstract coastal geologic records allow for the assessment of long term patterns of tropical cyclone variability however the accuracy of geologic reconstructions of tropical cyclones is limited by the lack of modern analogues we describe the microfossil foraminifera and testate amoebae assemblages contained within overwash sediments deposited by typhoon haiyan when it made landfall on the islands of leyte and samar in the philippines on 7 november 2013 as a category 5 super typhoon the overwash sediments were transported up to 1 7 km inland at four study sites the sediments consisted of light brown medium sand in a layer

sea level rise from glaciers and ice caps a lower bound 1 one of the most easily measured dimensions of a glacier the accumulation area is linked to future changes in glacier volume and consequent changes in sea level currently observed accumulation areas are too small forcing glaciers to lose 27 of their volume to attain equilibrium with current climate as a result at least 184 33 mm of sea level rise are necessitated by mass wastage of the world s mountain glaciers and ice caps even if the climate does not continue to warm if the climate continues to warm along current trends a minimum of 373 21 mm of sea level rise over the next 100 years is expected from glaciers and ice caps when compared to recent estimates from all other sources melt water from glaciers must be considered as a particularly important fraction of the total sea level rise expected this century

regional and global volumes of glaciers derived from statistical upscaling of glacier inventory data 1 very few global scale ice volume estimates are available for mountain glaciers and ice caps although such estimates are crucial for any attempts to project their contribution to sea level rise in the future we present a statistical method for deriving regional and global ice volumes from regional glacier area distributions and volume area scaling using glacier area data from 123 000 glaciers from a recently extended world glacier inventory we compute glacier volumes and their sea level equivalent sle for 19 glacierized regions containing all mountain glaciers and ice caps on earth on the basis of total glacierized area of 741 103 68 103 km2 we estimate a total ice volume of 241 103 29 103 km3 corresponding to 0 60 0 07 m sle of which 32 is due to glaciers in greenland and antarctica apart from the ice sheets however our estimate is sensitive to assumptions on volume area scaling coefficients and glacier area distributions in the regions that are poorly inventoried i e antarctica north america greenland and patagonia this emphasizes the need for more volume observations especially of large glaciers and a more complete world glacier inventory in order to reduce uncertainties and to arrive at firmer volume estimates for all mountain glaciers and ice caps

a new glacier inventory for the jostedalsbreen region norway from landsat tm scenes of 2006 and changes since 1966 pronounced changes in glacier mass and length were observed for the monitored glaciers in the jostedalsbreen region norway since the last glacier inventories were compiled in the 1960s and 1980s however the current overall extent of the glaciers in the region is not well known to obtain this information we have compiled a new inventory from two mosaicked landsat thematic mapper tm scenes acquired in 2006 that have excellent snow conditions for glacier mapping the first suitable scenes for this purpose after 22 years of imaging with tm drainage divides and topographic inventory parameters were derived from a 25 m national digital elevation model for 1450 glaciers by digitizing glacier outlines from 1 50 000 scale topographic maps of 1966 we calculated changes in glacier area for 300 glaciers cumulative length changes for the 1997 2006 period were derived from an additional tm scene and compared with field measurements for nine glaciers overall we find a 9 area loss since 1966 with a clear dependence on glacier size however seasonal snow in 1966 in some regions made area determination challenging the satellite derived length changes confirmed the observed high spatial variability and were in good agreement with field data 1 pixel apart from glacier tongues in cast shadow the new inventory will be freely available from the global land ice measurements from space glims glacier database

widespread and accelerating glacier retreat on the lyngen peninsula northern norway since their little ice age maximum the recession of mountain glaciers worldwide is increasing global sea level and in many regions human activities will have to adapt to changes in surface hydrology thus it is important to provide up to date analyses of glacier change and the factors modulating their response to climate warming here we report changes in the extent of 120 glaciers on the lyngen peninsula northern norway where glacier runoff is utilised for hydropower and where glacial lake outburst floods have occurred glaciers covered at least 114 km2 in 1953 and we compare this inventory with those from 1988 2001 and a new one from 2014 and previously dated little ice age lia limits results show a steady reduction in area 0 3 a 1 between their lia maximum 1915 and 1988 consistent with increasing summer air temperatures but recession paused between 1988 and 2001 coinciding with increased winter precipitation air temperatures increased 0 5 c per decade from the 1990s and the rate of recession accelerated to 1 a 1 between 2001 and 2014 when glacier area totalled 95 7 km2 small glaciers 0 05 km2 with low maximum elevations 1400 m experienced the largest percentage losses and if warming continues several glaciers may disappear within the next two decades

a new glacier inventory for the european alps from landsat tm scenes of 2003 challenges and results meltwater from glaciers in the european alps plays an important role in hydropower production and future glacier development is thus of economic interest however an up to date and alpine wide inventory for accurate assessment of glacier changes or modelling of future glacier development has not hitherto been available here we present a new alpine wide inventory covering austria france italy and switzerland derived from ten landsat thematic mapper tm scenes acquired within 7 weeks in 2003 combined with the globally available digital elevation model from the shuttle radar topography mission topographic inventory parameters were derived for each of the 3770 mapped glaciers covering 2050km2 the area class frequency distribution is very similar in all countries and a mean northerly aspect nw n ne is clearly favoured arithmetic counting mean glacier elevation is 2900 m with a small dependence on aspect the total area loss since the previous glacier inventory acquired around 1970 15 years is roughly one third yielding a current area loss rate of 2 a 1 digital overlay of the outlines from the latest austrian glacier inventory revealed differences in the interpretation of glacier extents that prohibit change assessment a comparison of tm derived outlines with manually digitized extents on a high resolution ikonos image returned 1 5 smaller glaciers with tm

the 2016 kumamoto mw 7 0 earthquake a significant event in a fault volcano system the 2016 kumamoto earthquake sequence occurred on the futagawa hinagu fault zone near the aso volcano on kyushu island the sequence was initiated with two major m w 6 0 foreshocks and the mainshock m w 7 0 occurred 25 h after the second major foreshock we combine gps strong motion synthetic aperture radar images and surface offset data in a joint inversion to resolve the kinematic rupture process of the mainshock and coseismic displacement of the foreshocks the joint inversion results reveal a unilateral rupture process for the mainshock involving sequential rupture of four major asperities the slip area of the foreshocks and mainshock and the aftershock loci form a detailed complementary pattern the mainshock rupture terminates near the rim of the caldera leaving a 10 km long gap of aftershocks this area is characterized by high temperature and low shear wave velocity density and resistivity which may be related to the partially melted geothermal condition ductile material property near the volcano may act as a material barrier to the dynamic rupture topographic weight of the caldera increases compressional normal stress on the fault plane which may behave as a stress barrier long term seismic hazard and deformation behaviors related to these two types of barriers are discussed in terms of the associated frictional mechanism significant postseismic creeps observed near the volcano area indicates a velocity strengthening frictional behavior near the rupture termination which confirms that the material barrier mechanism is likely the dominant rupture termination mechanism

an introduction to the global positioning system and some geological applications receivers equipped to measure dual frequency carrier phase signals from satellites of the global positioning system gps have been capable under special conditions of determining relative horizontal positions among stations separated by one to a few hundred kilometers with a precision of one to several millimeters since the early 1980s the major obstacles to making this capability routine extending it to all parts of the globe and extending it to longer station separations have been equipment cost limitations in the gps satellite constellation arduous data analysis uncertainties in satellite orbits uncertainties in propagation delays associated with variable tropospheric water vapor and difficulties in resolving carrier phase cycle ambiguities recent improvements have occurred in all these areas the increasing ease and reduced cost of gps data acquisition and analysis are having a significant impact on studies of near fault crustal deformation and earthquake processes until recently the province of conventional terrestrial geodetic techniques the enhanced satellite constellation improved models and establishment of global tracking networks have extended several millimeters horizontal positioning capability to station separations of 1000 km or more in virtually all parts of the world this enables study of new classes of tectonic problems that previously were difficult to attack with any geodetic technique examples include a complete kinematic description of ongoing crustal deformation in broad complex continental plate boundary zones and measurement of relative plate motion at convergent boundaries where global models may be poorly constrained

holocene glacier and climate fluctuations of the maritime ice cap hogtuvbreen northern norway holocene fluctuations of a small outlet glacier from the ice cap hogtuvbreen at 65 n in coastal northern norway are reconstructed based on distal glacier fed lake sediments complemented by a moraine sequence dated by lichenometry glaciers respond to changes in accumulation season precipitation ablation season temperature and redistribution of snow by wind hence reconstructions of glacier fluctuations based on distal glacier fed lakes may give detailed information about past climate at a potentially high temporal resolution yet the importance of any of these climate components is often difficult to solve here we apply the liestol relationship which expresses the relationship between ablation season temperature and annual accumulation of snow at the equilibrium line altitude ela to the reconstructed local temperature precipitation wind ela tpw ela to infer the relative importance of winter balance and ablation season temperature as causes of reconstructed glacier variation the reconstruct

geodetic model of the 2016 central italy earthquake sequence inferred from insar and gps data we investigate a large geodetic data set of interferometric synthetic aperture radar insar and gps measurements to determine the source parameters for the three main shocks of the 2016 central italy earthquake sequence on 24 august and 26 and 30 october mw 6 1 5 9 and 6 5 respectively our preferred model is consistent with the activation of four main coseismic asperities belonging to the sw dipping normal fault system associated with the mount gorzano mount vettore mount bove alignment additional slip equivalent to a mw 6 1 6 2 earthquake on a secondary 1 ne dipping antithetic fault and or 2 on a wnw dipping low angle fault in the hanging wall of the main system is required to better reproduce the complex deformation pattern associated with the greatest seismic event the mw 6 5 earthquake the recognition of ancillary faults involved in the sequence suggests a complex interaction in the activated crustal volume between the main normal faults and the secondary structures and a partitioning of strain release

a new glacier inventory for the svartisen region norway from landsat etm data challenges and change assessment glaciers are widely recognized as key indicators of climate change and their meltwater plays an important role in hydropower production in norway since the last glacier inventory was compiled in northern norway in the 1970s marked fluctuations in glacier length and mass balance have been reported for individual glaciers and the current overall glacier state is thus not well known within the framework of the global land ice measurements from space glims initiative we have created a new inventory for 489 glaciers in the svartisen region northern norway using a landsat enhanced thematic mapper plus etm satellite scene from 7 september 1999 and automated multispectral glacier mapping thresholded band ratios in addition visual inspection and correction of the generated glacier outlines has been applied adverse snow conditions and uncertain drainage divides made glacier mapping challenging in some regions of the study site glacier outlines from 1968 as digitized from a topographic map were used for a quantitative change assessment for a selection of 300 glaciers the overall area change of this sample from 1968 to 1999 was close to zero but with a strongly increasing scatter towards smaller glaciers large area gains 50 for small glaciers 1 km 2 and an unexpected stronger relative area loss towards the wetter coast the overall size changes are small 1 for the three largest ice masses in the study region vestisen ostisen and blamannsisen

a new interpretation of the date of the little ice age glacier maximum at svartisen and okstindan northern norway new results concerning the dating of little ice age glacier variations at svartisen and okstindan northern norway are presented measurements of lichens of the rhizocarpon subgenus on gravestones are used to construct several local sets of lichenometric dating curves these are partly adjusted in relation to well established lichenometric dating curves from southern norway the little ice age maximum at svartisen and okstindan is thereby dated to the mid eighteenth century i e in agreement with southern norway pre viously suggested earlier little ice age advances are demonstrated to have resulted from an underestimation of the growth rates of the rhizocarpon subgenus synchroneity of little ice age maxima in southern norway and at svartisen and okstindan suggest that a north south migration of latitudinal depressional tracks can be excluded as the main forcing factor as an alternative an increased se nw trend of moist air ow in winter parallel to the coast of norway is suggested as the

spatio temporal evolution of aseismic slip along the haiyuan fault china implications for fault frictional properties article history we use 20 years of synthetic aperture radar acquisitions by the ers and envisat satellites to investigate the spatial and temporal variations of strain rates along the 35 km long creeping section of the haiyuan fault at the north eastern boundary of the tibetan plateau we then use the derived displacements to infer the fault s frictional properties and discuss the relationship between creep and the seismic behavior of the fault located in between a millennial seismic gap and the 1920 m8 surface rupture trace this section has an average creep rate of 5 1m m yr about the interseismic loading rate the comparison of average surface velocity profiles derived from sar interferometry across the creeping section reveals a creep rate increase and or a creep migration to shallower depth between the 1990s and the 2000s we apply a smoothed time series analysis scheme on envisat insar data to investigate the creep rate variations during the 2004 2009 time period our analysis reveals that the creep rate accelerated in 2007 although data resolution does not allow to better constrain the onset of creep acceleration and its amplitude both decadal and short term transient behaviors are coeval with the largest earthquakes m 4 5 along the fault segment in recent years from the precise mapping of the surface fault trace we use the fault strike variations and the mohr circle construction to compute the along strike distribution of the friction coefficient along the creeping segment and compare it with the observed distribution of the creep rate we find that the creep rate scales logarithmically with the friction coefficient in agreement with the rate and state friction law in a rate strengthening regime the estimated value of log v 2 10 3 indicates that the earthquakes occurring along the creeping section cannot be the cause for a significant change in the overall segment s creep rate and that the recorded micro seismicity is most likely creep driven finally given the size and frictional properties of the creeping section we estimate based on previous models of dynamic rupture simulations a 0 20 probability for a rupture to break through this section together with the geometrical configuration of the haiyuan fault these results suggest that the creeping segment may act as a persistent barrier to earthquake propagation

glacial geomorphological mapping a review of approaches and frameworks for best practice geomorphological mapping is a well established method for examining earth surface processes and landscape evolution in a range of environmental contexts in glacial research it provides crucial data for a wide range of process oriented studies and palaeoglaciological reconstructions in the latter case providing an essential geomorphological framework for establishing glacial chronologies in recent decades there have been significant developments in remote sensing and geographical information systems gis with a plethora of high quality remotely sensed datasets now often freely available most recently the emergence of unmanned aerial vehicle uav technology has allowed sub decimetre scale aerial images and digital elevation models dems to be obtained traditional field mapping methods still have an important role in glacial geomorphology particularly in cirque glacier valley glacier and icefield ice cap outlet settings field mapping is also used in ice sheet settings but often takes the form of necessarily highly selective ground truthing of remote mapping given the increasing abundance of datasets and methods available for mapping effective approaches are necessary to enable assimilation of data and ensure robustness this paper provides a review and assessment of the various glacial geomorphological methods and datasets currently available with a focus on their applicability in particular glacial settings we distinguish two overarching work streams that recognise the different approaches typically used in mapping landforms produced by ice masses of different sizes i mapping of ice sheet geomorphological imprints using a combined remote sensing approach with some field checking where feasible and ii mapping of alpine and plateau style ice mass cirque glacier valley glacier icefield and ice cap geomorphological imprints using remote sensing and considerable field mapping key challenges to accurate and robust geomorphological mapping are highlighted often necessitating compromises and pragmatic solutions the importance of combining multiple datasets and or mapping approaches is emphasised akin to multi proxy approaches used in many earth science disciplines based on our review we provide idealised frameworks and general recommendations to ensure best practice in future studies and aid in accuracy assessment comparison and integration of geomorphological data these will be of particular value where geomorphological data are incorporated in large compilations and subsequently used for palaeoglaciological reconstructions finally we stress that robust interpretations of glacial landforms and landscapes invariably requires additional chronological and or sedimentological evidence and that such data should ideally be collected as part of a holistic assessment of the overall glacier system

gps observation of crustal deformation in the taiwan luzon region fifteen gps stations in the batan luzon area were surveyed three times during 1996 to 1998 in order to study crustal deformation in the taiwan luzon region the data from these annual surveys are processed together with data from 20 permanent stations in the taiwan area and igs stations in the asia pacific region we found that the chinese continental margin is moving in directions of 102 112 with rates of 11 12 mm yr relative to stable eurasia there is a significant southward increase in crustal motion with respect to eurasia along the n s trend of the luzon arc in the coastal range of taiwan the velocity is 53 mm yr in the direction 313 further south at two volcanic islands lanhsu and batan the velocities increase to 68 mm yr in the direction 306 and 81 mm yr in the direction 299 respectively in northern luzon the velocity reaches 86 mm yr in the direction 301 remarkable fault slips of 17 31 mm yr across the philippine fault system are detected

langfjordjokelen a rapidly shrinking glacier in northern norway in this paper we document changes of langfjordjokelen a small ice cap in northern norway surface mass balance measurements have been carried out on an east facing part 3 2 km 2 o f the ice cap since 1989 measurements reveal a strong thinning the balance year 2008 09 was the 13th successive year with significant negative annual balance 0 30 m w e the average annual deficit was 0 9 m w e over 1989 2009 the recent thinning of langfjordjokelen is stronger than observed for any other glacier in mainland norway maps from 1966 1994 and 2008 show that the whole ice cap is shrinking the total volume loss over 1966 2008 was 0 264 km 3 the east facing part has been greatly reduced in volume 46 area 38 and length 20 for this part over 1994 2008 the cumulative direct mass balance 14 5 m w e is less negative than the geodetic mass balance 17 7 m w e a surface mass balance model using upper air meteorological data was used to reconstruct annual balances back to 1948 and to reconstruct unmeasured years 1994 and 1995 sensitivity of annual balance to 18c warming is 0 76 m w e and to 10 increase in precipitation is 0 20 m w e

gps determined eastward sundaland motion with respect to eurasia confirmed by earthquakes slip vectors at sunda and philippine trenches abstract gps measurements acquired over southeast asia in 1994 and 1996 in the framework of the geodyssea program revealed that a large piece of continental lithosphere comprising the indochina peninsula sunda shelf and part of indonesia behaves as a rigid sundaland platelet a direct adjustment of velocity vectors obtained in a eurasian frame of reference shows that sundaland block is rotating clockwise with respect to eurasia around a pole of rotation located south of australia we present here an additional check of sundaland motion that uses earthquakes slip vectors at sunda and philippine trenches seven sites of the geodyssea network are close to the trenches and not separated from them by large active faults two at sumatra trench three at java trench and two at the philippine trench the difference between the vector at the station and the adjacent subducting plate vector defines the relative subduction motion and should thus be aligned with the subduction earthquake slip vectors we first derive a frame free solution that minimizes the upper plate or sundaland motion when corrected for australia eurasia and philippines eurasia nuvel1 a motion the misfit between gps and slip vectors azimuths is significant at 95 confidence indicating that the upper plate does not belong to eurasia we then examine the range of solutions compatible with the slip vectors azimuths and conclude that the minimum velocity of sundaland is a uniform 7 10 mm a eastward velocity however introducing the additional constraint of the fit of the geodyssea sites with the australian igs reference ones or tie with the ntus singapore station leads to a much narrower range of solutions we conclude that sundaland has an eastward velocity of about 10 mm a on its southern boundary increasing to 16 18 mm a on its northern boundary

a complete record of holocene glacier variability at austre okstindbreen northern norway an integrated approach arctic glaciers are currently undergoing major changes but accurate knowledge about how they varied during the entire holocene is still scarce here we present a new complete glacier record from austre okstindbreen in nordland northern norway this reconstruction is based on a number of short and long cores retrieved from several downstream basins which have been analyzed by a suite of methods including geochemical elements xrf rock magnetic properties dry bulk density dbd and loss on ignition loi lake sediment distribution was surveyed and mapped prior to coring by the use of ground penetrating radar gpr independently lichen dated marginal moraines and historical information about the glacier frontal positions from old photographs and maps have made it possible to link the moraine sequence to the 210pb dated lake sediment chronology this integrated approach reveals that austre okstindbreen is the first known glacier in scandinavia to possibly have survived the holocene thermal optimum it also brackets the four largest glacier advances to c 7400 7000 1400 1200 900 700 and 300 150 years before ad 2000 b2k in contrast to most reconstructed glaciers in scandinavia the largest glacier advance was not associated with the little ice age but rather to an earlier period centred at 1300 b2k both the moraine chronology and the lacustrine records document this neoglacial advance compared to other glacier reconstructions from the northern hemisphere we identify near synchronous glacier advances occurring roughly at 4000 b2k 2700 b2k 1300 b2k and during the little ice age these correlative advances across the northern hemisphere suggest that these observed centennial scale events are a shared feature regardless of the large geographical distances separating them some minor discrepancies between different geographical areas may be caused by lack of precise dating but local climatic conditions may play a role as well

the physical basis of glacier volume area scaling ice volumes are known for only a few of the roughly 160 000 glaciers worldwide but are important components of many climate and sea level studies which require water flux estimates a scaling analysis of the mass and momentum conservation equations shows that glacier volumes can be related by a power law to more easily observed glacier surface areas the relationship requires four closure choices for the scaling behavior of glacier widths slopes side drag and mass balance reasonable closures predict a volume area scaling exponent which is consistent with observations giving a physical and practical basis for estimating ice volumes glacier volume is insensitive to perturbations in the mass balance scaling but changes in average accumulation area ratios reflect significant changes in the scaling of both mass balance and ice volume

evolution of the norwegian plateau icefield hardangerjokulen since the little ice age the maximum little ice age lia glacier extent provides a significant baseline to assess long term glacier change and to place currently observed rates of glacier recession in a broader temporal

review of major shale dominated detachment and thrust characteristics in the diagenetic zone part ii rock mechanics and microscopic scale abstract characterising large shale thrust zone behaviour down to the diagenetic metamorphic boundary is both simple and complex the task in critical taper analogue and numerical models has been successfully approximated using simple material parameters yet the weakness of shales thrusts on a case by case basis show great variability in key factors across a wide range of scales understanding of these variables and their relationships to different tectonic settings is patchy due to the different objectives of workers studying the various systems e g seismic hazards hydrocarbon exploration structural geology research and the types of available geological and geophysical data early research recognized that megathrusts feature creeping and locked patches which may be described using the rate and state formalism in addition to temperature differential stress and strain rate key controlling factors on thrust weakness are mineralogy amount of weak phase present structure localization mechanisms grain size and shapes porosity permeability and pore fluid pressure the smectite illite transition has been a focus of seismic hazard research due to its coincidence with the top of the seismogenic zone while there may be a relationship other factors such as pore fluid pressure variations or structure localization are also important the critical taper model is a simple means of determining whether basic rock mechanics data e g frictional strength pore fluid pressure is appropriate for natural wedges for example aseismic basal detachments of gravity driven systems smaller critical taper wedges appear to retain higher pore fluid pressures along the basal detachment than seismogenic basal detachments higher critical taper wedges in many continental and deltaic fold and thrust belts high organic carbon content is a very important factor in shale weakness due to 1 the overall more ductile and well cleaved nature of the shale when organic content is high 2 the presence of high overpressures due to maturation of organic material and 3 metamorphism of carbon to low friction graphite this multifaceted influence of organic carbon content is just one example of the diversity of potential influences on shale thrust zone weakness which enable shales to be weak despite considerable lateral deposition related and vertical burial related changes in composition some key variations between different types of fold and thrust belt gravity driven accretionary prism andean himalayan type lie in systematic variations in clay mineralogy magnitudes and origins of overpressures seismic versus aseismic detachments and different structural localization mechanisms further research is required to explore the viability of such distinctions and their impact on structural styles

the impact of strike slip transtensional and transpressional fault zones on volcanoes part 1 scaled experiments the activity of a regional strike slip fault can affect or channel magma migration can deform a volcano and can destabilise the edifice flanks the aim of this study is to determine the location strike dip and slip of structures that develop in a stable or gravitationally spreading volcanic cone located in the vicinity of a fault with a strike slip component this problem is addressed with brittle and brittle ductile analogue models the one hundred and twenty three models were deformed by pure strike slip transtensional or transpressional fault displacements the deformation was organized around an uplift in transpressional and strike slip experiments and around a subsiding area in transtensional experiments most displacements are accommodated by a curved fault called sigmoid i structure which is a steep transpressional to transtensional fault this fault projects the regional fault into the cone and delimits a summit graben that is parallel to the main horizontal stress the systematic measurements of faults strike and slip in the experiments indicate that extension along the faults in the cone increases with the extensional component of the regional fault and the thickness of the substratum ductile layer the distribution of the fastest horizontal movements of the analogue cone flanks which vary depending on the regional fault characteristics and on the composition of the substratum correspond to the distribution of instabilities in nature natural examples of volcanoes sited in strike slip contexts are described and interpreted in the light of the analogue results in the second article

long term variations of the seasonal snow cover in nordland norway the influence of the north atlantic oscillation temporal and spatial variations of the seasonal snow cover at 40 sites in nordland county norway which lies across the arctic circle are examined since the last decade of the 19th century annual maximum snow depths have varied reflecting the interaction of synoptic conditions temperature and terrain north south and coastal inland differences are evident but common temporal trends are identified maximum snow depths are strongly related to the winter north atlantic oscillation index early in the 20th century the index was positive and the associated stormy conditions resulted in a deep prolonged snow cover as the index declined in the 1920s snow depths decreased sharply through much of the second half of the 20th century they increased as the index tended to become more positive the start and duration of the period of continuous snow cover is influenced by the autumn nao index a decrease of duration around 1990 was particularly evident at low lying stations and those in the northern part of nordland the nao has varied considerably over the past 120 years because of its influence forecasting future trends of snow depth and snow cover duration is not a simple task

geodetic constraints on coseismic rupture during the 1990 ms 7 8 luzon philippines earthquake 1 we analyze single frequency gps measurements taken before and after the july 16 1990 ms 7 8 luzon earthquake to constrain the faulting parameters of this major strike slip event the geodetic data imply fairly uniform left lateral slip of 5 5 6 5 m along the well mapped part of the fault trace in agreement with field mapping of the rupture and in general accord with seismological estimates of the fault parameters in addition we find that substantial slip of about 4 5 m magnitude continued about 40 50 km northward or northwestward into the cordillera central beyond the end of the mapped rupture this fault segment includes a substantial thrust component in addition to left lateral slip the geodetic data favor a faulting depth of at least 20 km along the central part of the rupture unusually deep for a major continental strike slip earthquake

an inverse approach to the course of the little ice age glacier advance and the following deglaciation at austerdalsisen eastern svartisen northern norway the course of the little ice age lia in scandinavia is characterized by large glacier advances that started at about ad 1300 and culminated at about ad 1750 the end of the lia is marked as an unprecedented and ongoing glacier retreat that accelerated from the early 20th century the course of the lia is here presented based on fluctuations of austerdalsisen the largest valley outlet glacier draining the austre svartisen ostisen ice cap nordland northern norway during the lia glacierization austerdalsisen separated into two branches and relative to the present glacier terminus a western valley glacier advanced more than 4 km whereas a se valley glacier advanced about 3 km at present meltwater from austerdalsisen drains towards se if the glacier obtains a critical magnitude however most of the meltwater is drained westwards across a higher overflow gap based on radiocarbon dated lake sediments distal proglacial glaciolacustrine glaciofluvial sediments and historical observations the c

from geodetic imaging of seismic and aseismic fault slip to dynamic modeling of the seismic cycle understanding the partitioning of seismic and aseismic fault slip is central to seismotectonics as it ultimately determines the seismic potential of faults thanks to advances in tectonic geodesy it is now possible to develop kinematic models of the spatiotemporal evolution of slip over the seismic cycle and to determine the budget of seismic and aseismic slip studies of subduction zones and continental faults have shown that aseismic creep is common and sometimes prevalent within the seismogenic depth range interseismic coupling is generally observed to be spatially heterogeneous defining locked patches of stress accumulation to be released in future earthquakes or aseismic transients surrounded by creeping areas clay rich tectonites high temperature and elevated pore fluid pressure seem to be key factors promoting aseismic creep the generally logarithmic time evolution of afterslip is a distinctive feature of creeping faults that suggests a logarithmic dependency of fault friction on slip rate

shallow slip of blind fault associated with the 2019 ms 6 0 changning earthquake in fold and thrust belt in salt mines of southeast sichuan china

upper plate deformation induced by subduction of a volcanic arc the snellius plateau molucca sea indonesia and mindanao philippines abstract the northern molucca sea shows the incipient subduction of a composite oceanic and arc volcanic block the snellius halmahera block shb multi beam reflectivity seismic and gravity data obtained during the modec marine survey showed that the shb disappears beneath the accretionary wedge and the outer ridge of the sangihe arc to the north in mindanao island ongoing convergence generated shortening of the forearc basin and the backthrusting of the shb meanwhile a classical system of paired subduction philippine trench and strike slip fault philippine fault was installed the transition from lithospheric subduction to crustal overthrusting is located where the philippine trench sensu stricto begins and also coincides with the off shore extension of the philippine fault we observe a reversal of the thrusts from an eastward vergence in the molucca sea to a westward vergence in mindanao island this reversal takes place at the latitude where the forearc area emerges by uplift and the downgoing crust shb deepens resulting in a strong gravity low centered above the accretionary wedge the philippine fault initiated in a place where the crust was sliced off by a transfer zone which marked the northern termination of the molucca sea and drags northward a sliver of the previously accreted shb the northward drifting of this sliver created an extension which however cannot account for the gravity low we propose that the shortening and the uplift of the upper plate were induced by the buoyancy of the subducted unit shb and triggered the thrust reversal

inferences drawn from two decades of alinement array measurements of creep on faults in the san francisco bay region we summarize over 20 years of monitoring surface creep on faults of the san andreas system in the san francisco bay region using alinement arrays the san andreas fault is fully locked at five sites northwest from san juan bautista the southern end of the 1906 earthquake rupture that is no creep 1 mm yr is observed likewise the san gregorio rodgers creek and west napa faults show no creep the measured creep rate on the calaveras paicines fault from hollister southward is either 6 or 10 mm yr depending on whether the arrays cross all of the creeping traces northward of hollister the central calaveras creep rate reaches 14 2 mm yr but drops to 2 mm yr near calaveras reservoir where slip transfers to the southern hayward fault at a maximum creep rate of 9 mm yr at its south end however the hayward fault averages only 4 6 mm yr over most of its length the northern calaveras fault now creeping at 3 4 mm yr steps right to the concord fault which has a similar rate 2 5 3 5 mm yr which is slightly slower than the 4 4 mm yr rate on its northward continuation the green valley fault the maacama fault creeps at 4 4 mm yr near ukiah and 6 5 mm yr in willits the central and southern segments of the calaveras fault are predominantly creeping whereas the hayward northern calaveras and maacama faults are partly locked and along with the rodgers creek and san andreas have high potential for major earthquakes manuscript received 6 november 2002

deformed symmetrical volcanoes analog modeling of volcanic cones traversed by strike slip faulting was conducted and the cones were analyzed for deformation characteristics the study shows that symmetrical volcanoes that have undergone basal strike slip offset may be deformed internally without manifesting any change in their conical shape volcanoes deformed by strike slip faulting may already have well developed fractures in their interior yet still appear as a symmetrical cone exhibiting concentric contours when viewed on a topographic map moreover slight changes in the basal shape of the cone induced by strike slip movement can be restored by the relatively faster resurfacing and reshaping processes from the deposition of younger eruptive products these findings pose a subtle but significant point in the assessment of volcanic landslide hazards not all perfect cones are undisturbed the detection of concealed deformation is important because fractures induce further instability in volcanoes and act as slip planes during volcano collapse events there are many examples of symmetrical volcanoes in nature the faultless appearance of such perfect cones can be misleading which requires careful attention in hazards assessment

a blind thrust and overlying folding earthquake of the 2016 mw 6 0 hutubi earthquake in the northern tien shan fold and thrust belts china

the randolph glacier inventory a globally complete inventory of glaciers the randolph glacier inventory rgi is a globally complete collection of digital outlines of glaciers excluding the ice sheets developed to meet the needs of the fifth assessment of the intergovernmental panel on climate change for estimates of past and future mass balance the rgi was created with limited resources in a short period priority was given to completeness of coverage but a limited uniform set of attributes is attached to each of the 198 000 glaciers in its latest version 3 2 satellite imagery from 1999 2010 provided most of the outlines their total extent is estimated as 726 800 34 000 km 2 the uncertainty about 5 is derived from careful single glacier and basin scale uncertainty estimates and comparisons with inventories that were not sources for the rgi the main contributors to uncertainty are probably misinterpretation of seasonal snow cover and debris cover these errors appear not to be normally distributed and quantifying them reliably is an unsolved problem combined with digital elevation models the rgi glacier outlines yield hypsometries that can be com bined with atmospheric data or model outputs for analysis of the impacts of climatic change on glaciers the rgi has already proved its value in the generation of significantly improved aggregate estimates of glacier mass changes and total volume and thus actual and potential contributions to sea level rise

a method to estimate the ice volume and ice thickness distribution of alpine glaciers sound knowledge of the ice volume and ice thickness distribution of a glacier is essential for many glaciological applications however direct measurements of ice thickness are laborious not feasible everywhere and necessarily restricted to a small number of glaciers in this paper we present a method to estimate the ice thickness distribution and the total ice volume of alpine glaciers this method is based on glacier mass turnover and principles of ice flow mechanics the required input data are the glacier surface topography the glacier outline and a set of borders delineating different ice flow catchments three parameters describe the distribution of the apparent mass balance which is defined as the difference between the glacier surface mass balance and the rate of ice thickness change and two parameters define the ice flow dynamics the method was developed and validated on four alpine glaciers located in switzerland for which the bedrock topography is partially known from radio echo soundings the ice thickness along 82 cross profiles can be reproduced with an average deviation of about 25 between the calculated and the measured ice thickness the cross sectional areas differ by less than 20 on average this shows the potential of the method for estimating the ice thickness distribution of alpine glaciers without the use of direct measurements

the relationship between seismic and aseismic slip on the philippine fault on leyte island bayesian modeling of fault slip and geothermal subsidence delineating seismic and aseismic slip on faults allows the exploration of the complex relationship between these different modes of slip further quantifying them helps in the assessment of seismogenic potential we present a distributed slip model of the rate of aseismic slip along the leyte island section of the philippine fault and make comparisons with the extent of seismic slip from the latest significant earthquakes in july 2017 we derived both coseismic and aseismic slip distributions from kinematic inversions of synthetic aperture radar interferometric insar observations using a probabilistic bayesian framework velocity maps from stacking and time series analysis of alos interferograms spanning 4 years 2007 2011 show a step change in ground deformation right on the fault inverting for slip at depth reveals along strike variations of aseismic slip rate over 100 km aseismic slip on the surface reaches rates of more than 3 cm yr equivalent to the long term slip rate 3 3 0 2 cm yr over the same period a 20 km segment in tongonan appears to be locked this segment ruptured in mw 6 5 and mw 5 8 earthquakes on 6 and 10 july 2017 respectively as constrained by sentinel 1 and alos 2 insar data seismic slip appears to be restricted within the tongonan segment with up to 152 21 cm of left lateral displacement the slip budget and complementarity between the extents of interseismic and coseismic slip suggest that a seismogenic asperity exists in tongonan the presence of active hydrothermal systems and rate strengthening materials provide physical conditions that can promote aseismic slip

using surface creep rate to infer fraction locked for sections of the san andreas fault system in northern california from alignment array and gps data surface creep rate observed along five branches of the dextral san andreas fault system in northern california varies considerably from one section to the next indicating that so too may the depth at which the faults are locked we model locking on 29 fault sections using each section s mean long term creep rate and the consensus values of fault width and geologic slip rate surface creep rate observations from 111 short range alignment and trilateration arrays and 48 near fault global positioning system station pairs are used to estimate depth of creep assuming an elastic half space model and adjusting depth of creep iteratively by trial and error to match the creep observations along fault sections fault sections are delineated either by geometric discontinuities between them or by distinctly different creeping behaviors we remove transient rate changes associated with five large m 5 5 regional earthquakes estimates of fraction locked the ratio of moment accumulation rate to loading rate on each section of the fault system provide a uniform means to inform source parameters relevant to seismic hazard assessment from its mean creep rates we infer the main branch the san andreas fault ranges from only 20 10 locked on its central creeping section to 99 100 on the north coast from mean accumulation rates we infer that four urban faults appear to have accumulated enough seismic moment to produce major earthquakes the northern calaveras m 6 8 hayward m 6 8 rodgers creek m 7 1 and green valley m 7 1 the latter three faults are nearing or past their mean recurrence interval online material high resolution fault system map and tables of creep observations and geographic coordinates of fault model

deformation and stress states along the central segmentof the philippine fault implications to wrench fault tectonics abstract this paper discusses the space time evolution of deformation and states of stress along the central segment of the left lateral philippine fault from bondoc peninsula to leyte island this segment is characterized by deformations and stress states which do not always conform to predictions of classical wrench tectonics directions of the maximum principal stress axis 1 are in some cases oriented perpendicular to the fault trace contradicting the classical fault strike 1 angle of 30 45 in other cases it is the minimum axis 3 that orients perpendicular to the fault or in other cases parallel to it rotations of 1 directions as functions of time and space are observed all along the fault more complex stress regimes are observed in areas where the philippine fault intersects with two other major left lateral strike slip faults namely the legaspi lineament in the ragay gulf area and the sibuyan sea fault in masbate these observations strongly underline the urgence of prudence and precaution in applying wrench fault tectonic principles in natural examples

philippine fault a key for philippine kinematics on the basis of new geologic data and a kinematic analysis we establish a simple kinematic model in which the motion between the philippine sea plate and eurasia is distributed on two boundaries the philippine trench and the philippine fault this model predicts a velocity of 2 to 2 5 cm yr along the fault geologic data from the visayas provide an age of 2 to 4 ma for the fault an age in good agreement with the date of the beginning of subduction in the philippine trench the origin of the philippine fault would thus be the flip of subduction from west to east after the locking of convergence to the west by the collision of the philippine mobile belt with the eurasian margin

active deformation in eastern indonesia and the philippines from gps and seismicity data in this study we combine global positioning system gps velocities with information on the style of regional seismicity to obtain a self consistent model velocity and strain rate field for the entire eastern indonesia and philippines region in the process of interpolating 93 previously published gps velocities the style and direction of the seismic strain rate field inferred from earthquakes with m0 1 1020 n m from the harvard centroid moment tensor catalog are used as constraints on the style and direction of model strain rates within the plate boundary zones the style and direction of the seismic strain rate field are found to be self similar for earthquakes up to m0 1 1020 n m equivalent to mw 7 3 our inversion result shows the following the java trench which lacks any significant historic seismicity delineates the australian plate au sunda block sunda plate boundary west of the island of sumba east of sumba convergence is distributed over the back arc and banda sea and there is no subduction at the timor trough suggesting that the northern boundary of the au plate runs north of this part of the banda arc through the banda sea in new guinea most motion is taken up as strike slip deformation in the northern part of the island delineating the pacific plate pa au boundary however some trench normal convergence is occurring at the new guinea trench evidence that the strain is partitioned in order to accommodate oblique pa au motion pa au motion is consistent with nuvel 1a direction but 8 mm yr 1 slower than the nuvel 1a estimate for pa au motion the sulawesi trench and molucca sea delineate zones of high strain rates consistent with high levels of active seismicity the sulawesi trench may take up some of the au sunda motion philippine sea plate motion is in a direction slightly northward of the nuvel ia estimate and is partitioned in some strike slip strain rates along the philippine fault and relatively larger trench normal convergence along the philippine trench and on the philippine mainland in the southern philippines and along the manila trench in the northern philippine islands the high level of strain rate along the manila trench is not released by any significant historic seismic activity for the entire eastern indonesia philippines region seismicity since 1963 has taken up 40 of the total moment rate inferred from our model

twentieth century contribution to sea level rise from uncharted glaciers global mean sea level rise gmslr during the twentieth century was primarily caused by glacier and ice sheet mass loss thermal expansion of ocean water and changes in terrestrial water storage1 whether based on observations2 or results of climate models3 4 however the sum of estimates of each of these contributions tends to fall short of the observed gmslr current estimates of the glacier contribution to gmslr rely on the analysis of glacier inventory data which are known to undersample the smallest glacier size classes5 6 here we show that from 1901 to 2015 missing and disappeared glaciers produced a sea level equivalent sle of approximately 16 7 to 48 0 millimetres missing glaciers are those small glaciers that we expect to exist today owing to regional analyses and theoretical scaling relationships but that are not represented in the inventories these glaciers contributed approximately 12 3 to 42 7 millimetres to the historical sle additionally disappeared glaciers those that existed in 1901 but had melted away by 2015 and that therefore cannot be included in modern global glacier inventories made an estimated contribution of between 4 4 and 5 3 millimetres failure to consider these uncharted glaciers may be an important cause of difficulties in closing the gmslr budget during the twentieth century their contribution is on average between 0 17 and 0 53 millimetres of sle per year compared to a budget discrepancy of about 0 5 millimetres of gmslr per year between 1901 and 1990 although the uncharted glaciers will have a minimal role in sea level rise in the future and are less important after 1990 these findings imply that undiscovered physical processes are not required to close the historical sea level budget from 1901 to 2015 missing and disappeared glaciers produced a rise in sea level that may enable the historical budget for global mean sea level rise to be closed without recourse to an undiscovered physical process

hillslope storage boussinesq model for subsurface flow and variable source areas along complex hillslopes 1 formulation and characteristic response 1 hillslope response to rainfall remains one of the central problems of catchment hydrology flow processes in a one dimensional sloping aquifer can be described by boussinesq s hydraulic groundwater theory most hillslopes however have complex three dimensional shapes that are characterized by their plan shape profile curvature of surface and bedrock and the soil depth field studies and numerical simulation have shown that these attributes are the most significant topographic controls on subsurface flow and saturation along hillslopes in this paper the boussinesq equation is reformulated in terms of soil water storage rather than water table height the continuity and darcy equations formulated in terms of storage along the hillslope lead to the hillslope storage boussinesq hsb equation for subsurface flow solutions of the hsb equation account explicitly for plan shape of the hillslope by introducing the hillslope width function and for profile curvature through the bedrock slope angle and the hillslope soil depth function we investigate the behavior of the hsb model for different hillslope types uniform convergent and divergent and different slope angles under free drainage conditions after partial initial saturation drainage scenario and under constant rainfall recharge conditions recharge scenario the hsb equation is solved by means of numerical integration of the partial differential equation we find that convergent hillslopes drain much more slowly compared to divergent hillslopes the accumulation of moisture storage near the outlet of convergent hillslopes results in bell shaped hydrographs in contrast the fast draining divergent hillslopes produce highly peaked hydrographs in order to investigate the relative importance of the different terms in the hsb equation several simplified nonlinear and linearized versions are derived for instance by recognizing that the width function of a hillslope generally shows smooth transition along the flow direction or by introducing a fitting parameter to account for average storage along the hillslope the dynamic response of these reduced versions of the hsb equation under free drainage conditions depend strongly on hillslope shape and bedrock slope angle for flat slopes of the order of 5 only the simplified nonlinear hsb equation is able to capture the dynamics of subsurface flow along complex hillslopes in contrast for steep slopes of the order of 30 we see that all the reduced versions show very similar results compared to the full version it can be concluded that the complex derivative terms of width with respect to flow distance play a less dominant role with increasing slope angle comparison with the hillslope storage kinematic wave model of troch et al 2002 shows that the diffusive drainage terms of the hsb model become less important for the fast draining divergent hillslopes these results have important implications for the use of simplified versions of the hsb equation in landscapes and for the development of appropriate analytical solutions for subsurface flow along complex hillslopes

seismotectonics of the 6 february 2012 mw 6 7 negros earthquake central philippines abstract at 03 49 utc on the 6th of february 2012 negros island in the visayan region of central philippines was struck by a magnitude mw 6 7 earthquake causing deaths of over 50 people and tremendous infrastructure damage leaving hundreds of families homeless the epicenter was located in the vicinity of the eastern coastal towns of la libertad and tayasan of the province of negros oriental earthquake induced surface deformation was mostly in the form of landslides liquefaction ground settlement subsidence and lateral spread there were no clear indications of a fault surface rupture the earthquake was triggered by a fault that has not been previously recognized earthquake data including epicentral and hypocentral distributions of main shock and aftershocks and focal mechanism solutions of the main shock and major aftershocks indicate a northeast striking northwest dipping nodal plane with a reverse fault mechanism offshore seismic profiles in the tanon strait between the islands of negros and cebu show a northwest dipping reverse fault consistent in location geometry and mechanism with the nodal plane calculated from earthquake data the earthquake generator is here proposed to be named the negros oriental thrust not geologic transects established from structural traverses across the earthquake region reveal an east verging fold thrust system in the latitude of guihulngan this fold thrust system is represented by the razor back anticline negros oriental thrust pair and by the pamplona anticline yupisan thrust pair in the latitude of dumaguete to the south together these active fold thrust systems are causing active deformation of the western section of the visayan sea basin under a compressional tectonic regime this finding contradicts previous tectonic models that interpret the tanon strait as a graben bounded on both sides by normal faults supposedly operating under an extensional regime the negros earthquake and the active fold thrust systems that were discovered in the course of the structural analysis provide strong arguments for basin inversion processes now affecting the visayan sea basin albeit under very slow strain rates derived from previous gps campaigns the occurrence of the earthquake in an area where no active faults have been previously recognized and characterized by slow present day strain rates underscores the necessity of paying more attention to and exerting more effort in the evaluation of earthquake hazards of regions that are seemingly seismically quiet especially when they underlie highly urbanized areas

western irian jaya the end product of oblique plate convergence in the late tertiary abstract the island of new guinea is the surface expression of the deformed northern margin of the australian continental block to the south undeformed continental crust is overlain by flat lying platform sediments that form a conformable sequence from late palaeozoic to late tertiary along the new guinea cordillera these platform sediments have been tightly folded and overthrust to the south as a result of crustal shortening caused by convergence between the australian plate and the pacific plate the earth movements resulting from this convergence started at the end of the miocene and continue to the present day it is postulated that all the major structures of western irian jaya were caused by this orogeny and can be explained by the convergence directed southwest northeast between the australian and pacific plates it is further postulated that the convergence has remained essentially constant since the start of the earth movements this convergence is consistent with that postulated in the circum pacific plate tectonic map aapg 1981 of 12 5 cm yr directed about 15 south of west only if the effects of the sorong yapen fault system are taken into account this complex east west trending fault system forms the southern boundary of the pacific plate and has responded to the convergence by left lateral strike slip displacement of at least 370 km since the late miocene as a consequence south of the sorong yapen fault system the convergence has been directed more to the south i e at least 45 south of west in this region south of the fault zones the north south component of the convergence has been accommodated in the east by folding and overthrusting over a wide zone of interaction called the new guinea mobile belt dow 1977 in the west on the other hand the australian continental crust has been a stable buttress kepala burung fig 2 which following convergence has protruded into the pacific plate its northeastern margin has therefore been exposed to the full brunt of collision with the pacific plate and large segments of continental crust have been broken off and rafted westwards in order to accommodate the difference in crustal shortening between the new guinea mobile belt and kepala burung two fundamental crustal fractures formed in the intervening region the waipoga and wandamen faults these fractures make angles of about 65 with the regional structural trend fig 2 and they were the focus of most of the resulting differential crustal displacement two of the more spectacular examples of this differential movement have been the thrusting of large slabs of crustal rocks tens of kilometres southwards over the australian continental crust weyland overthrust and lengguru fold belt

inference of multiple earthquake cycle relaxation timescales from irregular geodetic sampling of interseismic deformation abstract characterizing surface deformation throughout a full earthquake cycle is a challenge due to the lack of high resolution geodetic observations of duration comparable to that of characteristic earthquake recurrence intervals 250 10 000 years here we approach this problem by comparing long term geologic slip rates with geodetically derived fault slip rates by sampling only a short fraction 0 001 0 1 of a complete earthquake cycle along 15 continental strike slip faults geodetic observations provide snapshots of surface deformation from different times through the earthquake cycle the timing of the last earthquake on many of these faults is poorly known and may vary greatly from fault to fault assuming that the underlying mechanics of the seismic cycle are similar for all faults geodetic observations from different faults may be interpreted as samples over a significantly larger fraction of the earthquake cycle than could be obtained from the geodetic record along any one fault alone as an ensemble we find that geologically and geodetically inferred slip rates agree well with a linear relation of 0 94 0 09 to simultaneously explain both the ensemble agreement between geologic and geodetic slip rate estimates with observations of rapid postseismic deformation we consider the predictions from simple two layer earthquake cycle models with both maxwell and burgers viscoelastic rheologies we find that a two layer burgers model with two relaxation timescales is consistent with observations of deformation throughout the earthquake cycle whereas the widely used two layer maxwell model with a single relaxation timescale is not suggesting that the earthquake cycle is effectively characterized by a largely stress recoverable rapid postseismic stage and a much more slowly varying interseismic stage

large earthquakes and creeping faults faults are ubiquitous throughout the earth s crust the majority are silent for decades to centuries until they suddenly rupture and produce earthquakes with a focus on shallow continental active tectonic regions this paper reviews a subset of faults that have a different behavior these unusual faults slowly creep for long periods of time and produce many small earthquakes the presence of fault creep and the related microseismicity helps illuminate faults that might not otherwise be located in fine detail but there is also the question of how creeping faults contribute to seismic hazard it appears that well recorded creeping fault earthquakes of up to magnitude 6 6 that have occurred in shallow continental regions produce similar fault surface rupture areas and similar peak ground shaking as their locked fault counterparts of the same earthquake magnitude the behavior of much larger earthquakes on shallow creeping continental faults is less well known because there is a dearth of comprehensive observations computational simulations provide an opportunity to fill the gaps in our understanding particularly of the dynamic processes that occur during large earthquake rupture and arrest

volcano growth versus deformation by strike slip faults morphometric characterization through analogue modelling abstract volcanoes display diverse morphologies as a result of the complex interplay of several constructive and destructive processes scaled analogue models offer a tool to isolate and characterize the different processes here we investigate the interplay between volcano growth and deformation caused by an underlying strike slip fault through simple analogue models in particular we analyze the morphometry of analogue volcanoes resulting from different growth to deformation ratios deformation elongates the volcano edifice at an angle of 10 45 from the fault trace along the extensional quadrants and generates a summit graben structure oriented perpendicular to the edifice elongation the overall steepness of the edifice decreases but steep slopes are preserved or increased on the lower compressional flanks commonly related to small avalanches growth can partially to totally mask these features depending on the growth rate to strike slip velocity ratio the summit graben is easily masked even by low growth rates whereas edifice elongation has the best preservation potential scaling of the experiments suggests that at volcanoes with growth rate km3 yr to strike slip velocity km yr ratios 3 8 km3 km deformation features should be clearly preserved whereas at volcanoes with ratios 15 km3 km deformation features should be completely masked the typical growth rates of volcanoes 0 01 to 1 km3 ka and the typical velocities of strike slip faults 1 to 20 mm yr suggest that in nature growth rate to strike slip velocity ratios can range over 3 orders of magnitude spanning both types of end members using examples of both active and inactive volcanoes located on strike slip faults with variable elongation intensities and orientations we highlight that the analogue models account for some of the morphometric variability observed at volcanoes in nature although the role of vent distribution can be a key factor

estimation of the magnitudes and epicenters of philippine historical earthquakes abstract the magnitudes and epicenters of philippine earthquakes from 1589 to 1895 are estimated based on the review evaluation and interpretation of historical accounts and descriptions the first step involves the determination of magnitude felt area relations for the philippines for use in the magnitude estimation data used were the earthquake reports of 86 recent shallow events with well described effects and known magnitude values intensities are assigned according to the modified mercalli intensity scale of i to xii the areas enclosed by intensities iii to ix a iii to a ix are measured and related to magnitude values the most robust relations are found for magnitudes relating to a vi a vii a viii and a ix historical earthquake data are obtained from primary sources in libraries in the philippines and spain most of these accounts were made by spanish priests and officials stationed in the philippines during the 15th to 19th centuries more than 3000 events are catalogued interpreted and their intensities determined by considering the possible effects of local site conditions type of construction and the number and locations of existing towns to assess completeness of reporting of these events 485 earthquakes with the largest number of accounts or with at least a minimum report of damage are selected the historical epicenters are estimated based on the resulting generalized isoseismal maps augmented by information on recent seismicity and location of known tectonic structures their magnitudes are estimated by using the previously determined magnitude felt area equations for recent events although historical epicenters are mostly found to lie on known tectonic structures a few however are found to lie along structures that show not much activity during the instrumented period a comparison of the magnitude distributions of historical and recent events showed that only the period 1850 to 1900 may be considered well reported in terms of magnitude distribution each earthquake is evaluated for its quality of determination based on the number of intensity reports earlier than 1850 the data collected are few and most earthquakes had fewer than ten reports good quality reports began to be collected from 1850 partly correlative to an increase in the number of towns and partly to the start of a systematized collection of earthquake accounts by the manila observatory parameters of these well reported earthquakes may be used for conducting various seismological studies examples of how the parameters of poorly reported events were arrived at are also discussed

a two state integral balance model for soil moisture and groundwater dynamics in complex terrain a dynamical model is devised for a hydrologic system where unsaturated and saturated storage serve as the principal control on rainfall runoff and where complex topography drainage area and variable depth of moisture penetration describe the flow geometry the model is formed by direct integration of the local conservation equation with respect to the partial volumes occupied by unsaturated and saturated moisture storage respectively this yields an integral balance model in just two state variables the relationship of the dynamical model to field data in complex terrain is found through a joint probability density for terrain features this serves as a volume weighting function to construct conditional averages for the state variables and fluxes over a specified range of terrain features the scale of averaging could range from hillslopes to river basins two examples of the joint probability of terrain features altitude and aspect are demonstrated for valley ridge and appalachian plateau digital elevation models the strategy of a dynamical model formed by conditional averages of state variables with respect to terrain features is proposed as a way of simplifying the dynamics while preserving the natural spatial and temporal scales contributing to runoff response the parametric form of the storage flux or constitutive relationships for the proposed model is determined from numerical experiments in a simple hillslope flow geometry the results show that a competitive relation exists between unsaturated and saturated storage except for the lowest precipitation rates saturation overland flow is proposed to be a storage feedback relation solutions to the integral balance model are presented in terms of the phase portrait which represents all possible solution trajectories in state space the timing and magnitude of peaks in the runoff hydrograph from pulse type input events demonstrate quick flow from near stream saturated storage saturation overland flow including rejected rainfall storage feedback and late time infiltration from upslope subsurface flow

an 1899 glacier inventory for nordland northern norway produced from historical maps glaciers depicted on old maps reveal their historical extents before the advent of aerial and satellite remote sensing digital glacier inventories produced from these maps can be employed in assessments of centennial scale glacier change this study reconstructs the 1899 covering the period 1882 1916 glacier extent in nordland northern norway from historical gradteigskart maps with an emphasis on examining the accuracy of the mapped glaciers glacier outlines were digitised from georectified scans of the analogue maps in a raster graphics editor and were subsequently inventoried in a gis the accuracy of the historical glacier extent was established from written descriptions and landscape photographs created during the original field surveys and further validated against independent glacier outlines of 1 the maximum little ice age extent derived from geomorphological evidence and 2 the 1945 extent derived from vertical aerial photographs an overall uncertainty of 17 is associated with our inventory nordland s glaciers covered an area of 1712 291 km2 in 1899 by 2000 total ice cover had decreased by 47 807 137 km2 at a rate of 6 10 a 1 80 14 km2 10 a 1 the approach presented here may serve as a blueprint for future studies intending to derive glacier inventories from historical maps