natural magnetic disturbance fields not precursors preceding the loma prieta earthquake 1 available records of the magnetic indices dst and ap together with standard observatory recordings of 1 min field levels were examined for the period preceding the earthquake of october 1989 centered near loma prieta california the magnetic records showed that the fraser smith et al 1990 report claiming the existence of a 100 s ultralow frequency geomagnetic field precursor signal at corralitos california foretelling a nearby earthquake is not valid my study shows that the stanford ulf signal was not local but rather widespread throughout the western united states and therefore expected to be due to a coincidental geomagnetic solar terrestrial disturbance field

palaeoclimatic implications of the occurrence of the arcoid bivalve anadara trapezia deshayes in the quaternary of australasia abstract the arcoid bivalve anadara trapezia deshayes 1840 is a eurythermal estuarine mollusc that flourishes at present in eastern australia between port phillip bay victoria and townsville in northern queensland a trapezia first appeared in the australian quaternary fossil record during oxygen isotope stage ois 7 in new zealand where it is now extinct the earliest known occurrences are in the rangitawa fossil beds and in uppermost castlecliffian strata west of wanganui north island ois 11 ca 400 ka the species had an extensive distribution during the last interglacial maximum ois 5e in both australia and new zealand and appears to have had a slightly wider than present geographic range in southeastern australia during the middle holocene as shown by records from tasmania and western victoria where it no longer lives apart from an isolated population inhabiting oyster harbour western australia a trapezia has not been confirmed living in coastal waters west of port phillip bay victoria it became extinct in new zealand sometime after ois 5e the extensive distribution and abundance of a trapezia and other fauna of subtropical affinity during the last interglacial maximum in areas where both are now extinct appears to be associated with an enhanced leeuwin current at that time coinciding with higher less seasonally concentrated levels of precipitation and river discharge the arrival of a trapezia in australasian coastal waters may have been a consequence of planktonic dispersal from southern south america a bravardi del rio from the middle miocene puerto madryn formation on the valdes peninsula argentina may be a possible ancestor for a trapezia

geological evidence for past large earthquakes and tsunamis along the hikurangi subduction margin new zealand abstract the hikurangi subduction margin new zealand has not produced large subduction earthquakes within the short written historic period 180 years and the potential of the plate interface to host large m 7 to great m 8 earthquakes and tsunamis is poorly constrained the geological record of past subduction earthquakes offers a method for assessing the location frequency and approximate magnitude of subduction earthquakes to underpin seismic and tsunami hazard assessments we review evidence of holocene coseismic coastal deformation and tsunamis at 22 locations along the margin a consistent approach to radiocarbon age modelling is used and earthquake and tsunami evidence is ranked using a systematic assessment of the quality of age control and the certainty that the event in question is an earthquake to identify possible subduction earthquakes we use temporal correlation of earthquakes combined with the type of earthquake evidence likely primary fault source and the earthquake certainty ranking we identify 10 past possible subduction earthquakes over the past 7000 years along the hikurangi margin the last subduction earthquake occurred at 520 470 years bp in the southern hikurangi margin and the strongest evidence for a full margin rupture is at 870 815 years bp there are no apparent persistent rupture patches suggesting segmentation of the margin is not strong in the southern margin the type of geological deformation preserved generally matches that expected due to rupture of the interseismically locked portion of the subduction interface but the southern termination of past subduction ruptures remains unresolved the pattern of geological deformation on the central margin suggests that the region of the interface that currently hosts slow slip events also undergoes rupture in large earthquakes demonstrating different modes of slip behaviour occur on the central hikurangi margin evidence for subduction earthquakes on the northern margin has not been identified because deformation signals from upper plate faults dominate the geological record large uncertainties remain in regard to evidence of past subduction earthquakes on the hikurangi margin with the greatest challenges presented by temporal correlation of earthquake evidence when working within the uncertainties of radiocarbon ages and the presence of upper plate faults capable of producing deformation and tsunamis similar to that expected for subduction earthquakes however areas of priority research such as improving the paleotsunami record and integration of submarine turbidite records should produce significant advances in the future

modeling suspended sediment discharge from the waipaoa river system new zealand the last 3000 years hydrotrend a hydrologic transport model is used to simulate the water and suspended sediment discharge of the waipaoa river system over the last 3 kyr a time period in which a well documented sequence of natural events and anthropogenic activities that profoundly impacted drainage basin processes occurred comparisons between observed and simulated data show that the model output replicates the frequency and distribution of flow events and the suspended sediment concentration discharge relationship and the long term trends in suspended sediment discharge are consistent with the sediment record preserved on the middle shelf water discharge tracks precipitation and average annual discharge may have been up to 20 higher and 6 lower at different times in the past suspended sediment discharge changed from 2 3 4 5 to 14 9 8 7 mt yr 1 during the anthropocene increasing by 140 after polynesian arrival by 350 after european colonization and by 660 after the catchment headwaters were deforested

on the ulf magnetic ratio increase before the 2008 iwate miyagi nairiku earthquake by hirano and hattori 2011 abstract hirano and hattori 2011 hereafter cited as h h report the observation of anomalous increases in the ulf geomagnetic field spectral density ratio which the authors claim to be possible precursors of the 2008 iwate miyagi nairiku earthquake here the results of h h are reviewed taking into account the global geomagnetic activity level by means of k p index this paper cast serious doubts on the seismogenic origin of the magnetic signatures documented by h h showing that the anomalous signals are normal ulf magnetic variations induced by solar terrestrial interaction in summary h h s claims that magnetic field disturbances about a month before the mw 6 9 iwate miyagi nairiku earthquake on june 13 2008 are precursors to the earthquake are unlikely to be correct

are there new findings in the search for ulf magnetic precursors to earthquakes moore 1964 in a letter published in nature reported disturbances in geomagnetic field data prior to the 27 march 1964 alaska earthquake after the publication of this report many papers have shown magnetic changes preceding earthquakes however a causal relationship between preearthquake magnetic changes and impending earthquakes has never been demonstrated as a consequence after 50 years magnetic disturbances in the geomagnetic field are still candidate precursory phenomena some researchers consider the investigation of ultra low frequency ulf 0 001 10 hz magnetic data the correct approach for identifying precursory signatures of earthquakes other researchers instead have recently reviewed many published ulf magnetic changes that preceded earthquakes and have shown that these are not actual precursors the recent studies by currie and waters 2014 and han et al 2014 aim to provide relevant new findings in the search for ulf magnetic precursory signals however in order to contribute to science alleged precursors must be shown to be valid and reproducible by objective testing here we will briefly discuss the state of the art in the search for ulf magnetic precursors paying special attention to the recent findings of currie and waters 2014 and han et al 2014 we do not see in these two reports significant evidence that may support the observation of precursory signatures of earthquakes in ulf magnetic records

on claimed ulf seismogenic fractal signatures in the geomagnetic field 1 during the last ten years fractal analysis of ultra low frequency ulf geomagnetic field components has been proposed as one of the most promising tools to highlight magnetic precursory signals possibly generated by the preparation processes of earthquakes several papers claim seismogenic changes in the fractal features of the geomagnetic field some months before earthquakes occur the target of the present paper is to put forth a qualitative investigation on the fractal characteristics of ulf magnetic signatures that previous authors have claimed to be related without doubt to strong earthquakes this analysis takes into account both the temporal evolution of the geomagnetic field fractal parameters reported in previous researches and the temporal evolution of global geomagnetic activity running averages of the geomagnetic indices kp and ap are plotted into the original figures from the previous publications this simple analysis shows that the fractal features of the ulf geomagnetic field are closely related to the geomagnetic activity both before and after the earthquake occurs the correlation between the geomagnetic field fractal parameters and geomagnetic activity is clearly shown over both long and short time scales in light of this the present paper shows that fractal behaviors of previously claimed seismogenic ulf magnetic signatures depend mainly on geomagnetic activity due to solar terrestrial interaction therefore previously reported association with the preparation process of the earthquake is dubious

holocene shoreline depositional processes at poverty bay a tectonically active area northeastern north island new zealand abstract holocene depositional processes at poverty bay have been affected by 1 tectonism 2 sea level response to climate change 3 fluvial processes responding to 1 and 2 severe storms and volcanic eruptions the height distribution of radiocarbon dated beach and estuarine shells and wood show that during the holocene relative uplift of the land has occurred at the northeastern margin of the poverty bay flats while subsidence has occurred at the southwestern margin three holocene tectonic subregions are distinguished at the poverty bay flats coast a northern gisborne wainui uplift area a central makaraka awapuni static pivotal area and a southern patutahi muriwai downdrop area periods of significant fluvial upstream degradation into gravel terrace deposits and downstream gravel aggradation are dated at ca late last glaciation 12 000 9000 and 7000 5000 bp the 12 000 9000 bp gravel deposits show tilting to the southwest major erosion and infilling events also occurred at ca 1700 and 300 bp holocene marine transgression and progradation shoreline locations are mapped and the coastal processes are reviewed in terms of the tectonic fluvial and eustatic sea level influences

coseismic uplift of holocene marine terraces in the pakarae river area eastern north island new zealand abstract holocene marine terraces along 15 km of the northeastern coast of north island record episodic tectonic uplift a maximum of seven terraces are arranged in staircase fashion and lie about 20 km above the subduction interface between the pacific and australian plates the highest t1 corresponds with the maximum of the holocene marine transgression about 6700 14 c yr b p younger terraces are marine abrasion platforms overlain by thin beach deposits radiocarbon ages of marine shells from beach deposits indicate that uplift above marine conditions occurred ca 6700 t1 5500 t2 3900 t3 2500 4 1600 t5 1000 t6 and slightly younger than 600 t7 yr b p uplift probably occurred coseismically the maximum late holocene uplift rate in the study area is 8 mm yr altitudinal distribution of terraces suggests deformation exists as a ca 20 km elongate dome broken at the southern end by the pakarae fault which trends across the dome rupture on this fault has accompanied the growth of the dome but is not responsible for it bathymetric profiling suggests that an active fault parallel to and about 5 km offshore is probably responsible for the episodic coastal uplift

on the seismogenic increase of the ratio of the ulf geomagnetic field components abstract following the paper by fraser smith et al 1990 many scientists have focused their research on the ulf geomagnetic field pulsations in the hope of finding possible anomalous signals caused by the seismic activity thereafter many papers have reported ulf geomagnetic field polarization ratio increases which have been claimed to be related to the occurrence of moderate and strong earthquakes even if there is no firm evidence of correlation between the polarization ratio increase and seismic events these publications maintain that these anomalous increases are without doubt precursors of pending earthquakes furthermore several researchers suggest that these seismogenic signals may be considered a promising approach towards the possibility of developing short term earthquake prediction capabilities based on electromagnetic precursory signatures on the contrary a part of the scientific community emphasizes the lack of validation of claimed seismogenic anomalies and doubt their association with the seismic activity since earthquake prediction is a very important topic of social importance the authenticity of earthquake precursors needs to be carefully checked the aim of this paper is to investigate the reliability of the ulf magnetic polarization ratio changes as an earthquakes precursor several polarization ratio increases of the geomagnetic field which previous researchers have claimed to have a seismogenic origin are put into question by a qualitative investigation the analysis takes into account both the temporal evolution of the geomagnetic field polarization ratio reported in previous papers and the global geomagnetic activity behaviour running averages of the geomagnetic index k p are plotted onto the original figures from previous publications moreover further quantitative analyses are also reported here nine cases are investigated which include 17 earthquakes in seven cases it is shown that the suggested association between the geomagnetic field polarization ratio increases and the earthquake preparation process seems to be rather doubtful more precisely the claimed seismogenic polarization ratio increases are actually closely related to decreases in the geomagnetic activity level furthermore the last two investigated cases seem to be doubtful as well although a close correspondence between polarization ratio and geomagnetic activity cannot be unambiguously demonstrated

signals of watershed change preserved in organic carbon buried on the continental margin seaward of the waipaoa river new zealand abstract holocene sediments buried on the continental shelf seaward of the waipaoa river northeastern new zealand preserve a stratigraphic record of terrestrial environmental change the well characterized long term record of storms volcanism and human disturbance in this region provides an opportunity to examine how such changes are reflected in the character of organic carbon oc buried on the continental margin complimentary evidence obtained from analyses of the 14 c content and the elemental and stable carbon isotopic composition of different sedimentary fractions including charcoal wood and clay sized isolates indicates that these perturbations led to mobilization of oc components with variable storage histories in the watershed charcoal transported in the modern waipaoa river and buried in offshore depocenters includes a highly aged component that has apparently been slowly released from storage in soil or alluvial terraces the charcoal fraction ages become dramatically younger in sediments deposited after the taupo volcanic eruption 1717 cal yr bp and then polynesian settlement ca 700 cal yr bp both signaling biomass burning the mean age of woody plant fragments and clay bound oc deposited on the shelf also varies over time with older material having accumulated in the middle holocene and since human occupation deposition of older than average wood fragments and clay bound oc between about 5 and 3 6 kyr bp correlates with evidence for a period of increased storm frequency in the region and may reflect the enhanced delivery of aged soil and sedimentary rock mobilized from hill slopes via earthflows and or deep seated landslides similarly the deposition of older wood and clay bound oc commensurate with the first anthropogenic disturbance ca 700 years ago is consistent with accelerated mass wasting due to deforestation at the same time a change in the elemental and stable isotopic composition of bulk and clay bound oc buried on the shelf may reflect increased marine primary productivity and or mobilization of oc from deep levels in soil profiles deforestation of the waipaoa headwaters by european settlers beginning in the middle 19th century is evinced by a sharper rise in the age of clay associated oc buried offshore today deep gully incision into fractured sedimentary bedrock is a major source of sediment and kerogen to the river and this process has left its mark on the age of sedimentary oc delivered to the adjacent margin

a source to sink perspective of the waipaoa river margin abstract a fundamental goal of the earth science community is to understand how perturbations on earth s surface are preserved in the stratigraphic record recent source to sink s2s studies of the waipaoa sedimentary system wss new zealand are synthesized herein to provide a holistic perspective of the processes that generate transport and preserve sedimentary strata and organic carbon on the waipaoa margin in the late quaternary rapid uplift associated with subduction processes and weak sedimentary units have conspired to generate rapid rates of incision and erosion in the waipaoa catchment since the last glacial maximum lgm we show that although much of the sediment exported offshore during this time interval originated from valley excavation a substantial portion emanated from hillslopes mostly through deep seated landslide and earthflow processes that were vigorous during periods of rapid fluvial incision just prior to the pleistocene holocene transition lacustrine sediments deposited in naturally dammed 7 ky old lake tutira provide a record of holocene environmental controls on upper catchment sedimentation in the wss with 1400 storms identified storm frequency is modulated by the waxing and waning of atmospheric teleconnections between the tropics and antarctica furthermore clear long term changes in sediment yield are evident from the lake tutira record following human settlement as conversion to pasture is accompanied by a 3 fold increase in the long term lake sediment accumulation rate whereas there is ample evidence that waipaoa river flood deposits are routinely deposited offshore in the sheltered confines of poverty bay over the longer term waves and currents subsequently resuspend and transport these deposits both landward sandy fraction and seaward finer fraction thus the timing of sediment supply to areas of net sediment accumulation is more often driven by wave events that are not associated with river flooding therefore we conclude that asynchronicity of river sediment delivery and of wave resuspension in most instances precludes the direct preservation of flood events in the stratigraphic record of the waipaoa shelf over the longer term the sediment package preserved on the shelf and slope since the lgm can be explained in large measure by sequence stratigraphic models forced by varying sea level and ongoing tectonic deformation of the margin as sea level rose sediment supply to the slope was reduced by about a factor of 5 due to shelf trapping despite this reduction turbidites are found at similar frequency throughout the lgm present as the dominant trigger appears to be subduction earthquakes with large ones having a return interval of about 200 100 years sediment budget exercises that consider both modern river discharge versus centennial accumulation rates and post lgm terrestrial production versus offshore isopachs mass balances indicate that about half of the total sediment production from the waipaoa escapes the study area moreover a coupled sediment transport hydrodynamic model and observations of textural trends on the shelf indicate that a large fraction of the sediment is carried outside the study area along the shelf to the northeast by the river plume or by combined current wave activity therefore we conclude that the wss is an open system with sediment escape from the present day through the lgm the organic matter associated with sediment as it moves from upland source to marine sink is a product of particle history and provides a record of materials that have cycled over timescales of days to millions of years the ubiquity of fossil organic carbon oc in both the terrestrial and marine realms of the waipaoa attests both to the chronic nature of its source crumbling mudstones further destabilized by land use and its biogeochemical recalcitrance modern oc persists by virtue of its continual production along the s2s transit and is buried and preserved within the adjacent marine depocenters the waipaoa contrasts with dispersal systems on wide energetic shelves e g the amazon and fly rivers where sediment is extensively refluxed in oxygenated overlying water resulting in the biogeochemical incineration of particulate oc the waipaoa like other small mountainous rivers on active margins exhibits a high riverine oc preservation efficiency 50 in its marine depocenters because of the relatively rapid event driven accumulation of sediment

el nino southern oscillation signal associated with middle holocene climate change in intercorrelated terrestrial and marine sediment cores north island new zealand a synchronous textural variation in intercorrelated high resolution sediment records from floodplain continental shelf and continental slope settings of the eastern north island new zealand provides evidence of increased storminess after ca 4 ka an upcore change in sediment texture reflects the transition to landsliding which supplanted fluvial incision as the dominant mode of sediment production in the middle holocene this signal which appears in all three records indicates a regional response to external forcing and records the impact of an intensified atmospheric circulation marking the establishment of the contemporary climate that is strongly influenced by the el nino southern oscillation the change in climate was a hemispheric event and in the southern hemisphere its timing is confirmed by independent proxy records from elsewhere in new zealand and the circum south pacific region

on the reported magnetic precursor of the 1993 guam earthquake 1 using 1 second magnetometer data recorded 67 km from the epicenter of the 1993 mw 7 7 guam earthquake hayakawa et al 1996 and miyahara et al 1999 identify anomalous precursory changes in ultra low frequency magnetic polarization the ratio of vertical to horizontal field components in a check of their results we compare their data gam with 1 second data from the kakioka observatory kak in japan and the global magnetic activity index kp we also examine log books kept by usgs staff working on the guam magnetic observatory we find 1 analysis problems with both hayakawa et al and miyahara et al 2 significant correlation between the gam kak and kp data and 3 an absence of identifiable localized anomalous signals occurring prior to the earthquake the changes we do find in polarization are part of normal global magnetic activity they are unrelated to the earthquake

downstream fining in a rapidly aggrading gravel bed river downstream changes in particle size that occur in the waipaoa river a 104 km long gravel bed river in which rapid aggradation in the historic post 1800 period was triggered by the conversion of native forest to pasture are summarized in this paper the textural data presented are unique for a field situation not only because of the spatial resolution and extent of the sampling program but also because they provide information about the pattern of fining at different points in time they are supported by equally comprehensive topographic survey data from which local rates of aggradation can be derived despite variability induced by lateral sediment inputs there is an essentially continuous pattern of fining along the entire length of the river fining occurs in both the fine and coarse size fractions of the bed material the highest rates of fining occur in the larger percentiles of the subsurface bed material and in the surface bed material downstream fining in the waipaoa river appears to be a response to changes in flow hydraulics that are regulated by the concave configuration of the long profile the fining gradient developed rapidly in 45 years it does not appear to be influenced by the rate of aggradation nor the overall rate of sediment supply to the channel system because in the short term aggradation has a negligible impact on the inherited form of the long profile

the post glacial downcutting history in the waihuka tributary of waipaoa river gisborne district implications for tectonics and landscape evolution in the hikurangi subduction margin new zealand abstract determining the spatial and temporal deliveries of sediment from the waipaoa river catchment in the post glacial period is a major goal of integrated source to sink landscape evolution studies in the region in a 2 2 km long section of the waihuka tributary 217 km 2 of the waipaoa river 2150 km 2 in eastern north island new zealand a sequence of at least ten fluvial terraces and abandoned meanders up to 45 m above the present river records rates and times of post glacial downcutting dateable organic and tephra horizons in the terrace and meander infill stratigraphy indicate that downcutting at this location on the waihuka tributary was dominated by a short lived event in the early holocene from 10 8 ka bp when as much as half of the downcutting was accomplished in only 10 15 of post glacial time the large downcutting event is interpreted to record the passing of a succession of major knickpoints or a knickzone through this tributary the initiation of knickpoint retreat in the catchment was primarily a consequence of reduction in sediment supply at the end of mis 2 based on the timing of rapid downcutting in the waipaoa river mainstem we estimate that the rate of knickpoint retreat along the waihuka tributary was about 2 km kyr in the period before and after rapid downcutting in the waihuka tributary modest incision rates averaging 1 2 mm yr probably represent the regional tectonic uplift rate

from mountain source to ocean sink the passage of sediment across an active margin waipaoa sedimentary system new zealand abstract the joint us nz source to sink initiative aims to unravel the tectonic climatic and other processes that shape the landscape from the mountains to deep ocean of two focus areas chosen world wide the waipaoa sedimentary system wss of north eastern new zealand was identified as an example of a mid latitude high sediment input system it resides within the westerly wind belt and extends across the convergence zone of the australian and pacific plates accordingly the tectonic and climatic drivers are prominent and their influences on the wss are decipherable as is documented in the suite of source to sink studies presented in this special issue of marine geology the wss is forced at several temporal and spatial scales which collectively appear as short term events storms earthquakes and volcanic eruptions superimposed on long term behavioural shifts tectonic uplift and eustatic sea level change overall the wss is undergoing uplift which has been contributing to valley incision since the last glacial maximum uplift is both gradual and intermittent the latter relating to fault and subduction related earthquakes such seismic activity destabilises the landscape and together with frequent storms generates large amounts of sediment as this sediment passes through the system part is captured in traps formed by local subsidence of the coastal plain and middle continental shelf where large thicknesses of holocene and probably older sediment are sequestered e g 200 m under the coastal plain nevertheless substantial sediment still reaches the continental slope to accumulate in canyon heads and slope basins with other deposits redistributed down slope in mass flows major volcanic eruptions also affect the sediment flux via direct input from ash fall and by enhanced erosion following volcanic destruction of terrestrial vegetation frequent storms of varying intensity play a key role in the generation and transfer of sediment major events such as cyclone bola of 1988 inundated the shelf with sediment but identifiable flood deposits were preserved only locally attesting to the effectiveness of shelf physical and biological mixing regimes despite the storms earthquakes and volcanic eruptions the largest perturbation of the wss at least in the last 2400 years has been the human deforestation of the landscape the resultant influx of sediment overwhelmed the shelf s storage capacity instead of capturing 90 the fluvial input as in pre human times the modern shelf retains only 25 the remainder escaping to the slope and elsewhere

slip slidin away a post glacial environmental history of the waipaoa river basin abstract the dramatic changes that occurred to the post glacial landscape in the headwaters of the waipaoa river basin are a consequence of perturbations about the equilibrium that exists between the rate of tectonic uplift and fluvial incision at times when the amount of coarse sediment delivered to channels exceeds the capacity of streams to remove it the channel bed rises at the rate of tectonic uplift once bedload overcapacity is replaced by undercapacity and the alluvial cover is depleted streams reestablish contact with bedrock and recuperate the time lost to fluvial incision the first major perturbation occurred during the final phase of the last glaciation ca 33 17 5 cal ka when aggradation was driven by a climate forced variation in the relative supplies of sediment and water we suggest that the subsequent transformation of channels in the headwaters of the waipaoa river basin from alluvial to bedrock occurred as the atmospheric and oceanic circulation converged on their contemporary patterns ca 12 cal ka a second major perturbation that continues to the present began ca 1910 1912 ce when a massive increase in sediment load was accompanied by a modest increase in water discharge after the native vegetation cover in the headwaters was replaced by pasture the processes of terrace creation and incision are inherently unsteady and in five interim cases incision was arrested by a transient increase in the thickness of the alluvial cover that was a response to climatic forcing events that disrupted the native vegetation cover in the headwaters also modulated patterns of sediment dispersal and accumulation in other parts of the fluvial system and caused rapid storm driven infilling of the poverty bay flats tectonic subsidence dictates the course of the waipaoa river across poverty bay flats which because the modern rate of floodplain construction by vertical accretion is rapid relative to the amount of destruction by lateral channel migration has remained virtually unchanged for the past 100 years during this time the channel assumed a narrower deeper form that is in equilibrium with the contemporary supply of sediment and hydraulic regime

fractal analysis of ulf geomagnetic data associated with the guam earthquake on august 8 1993 this paper presents a fractal analysis of the ulf electromagnetic data obtained at guam observatory during a strong ms 8 0 earthquake occurred on august 8 1993 near the guam island we have already reported the presence of seismogenic ulf emissions for this quake hayakawa et al grl 1996 the chosen period covered four months before and two months after the earthquake it was found that the spectrum of emissions at noon exhibited a power law behavior f which is typical for self organized critical dynamics the slope of the spectrum in the noon sector fluctuates in a range from 2 5 to 0 7 with a tendency to gradually decrease during the process of the earthquake preparation we consider this to be a candidate for a precursory signature the similar effect was found for the night sector we suggest that the focal zone was at the critical stage of self organized criticality process before the quake related to active microfracturing processes followed by the generation of ulf emissions as we detected

contrasting modes of shelf sediment dispersal off a high yield river waiapu river new zealand abstract recent studies of continental margins suggest that small high yield rivers are capable of generating shelf sediment gravity flows an idea that fundamentally alters our understanding of material flux from the continents to the ocean discharge measurements indicate that the waiapu river north island new zealand reaches hyperpycnal concentrations 36 kg m 2 on a yearly basis this study contrasts shelf edge basins with a broad trough along the shelf edge off the waiapu river testing whether there is evidence that shelf sediment gravity flows propagate to topographic lows observations and measurements through geochemical and sedimentological analyses of sediment cores em1002 swath bathymetry and chirp sub bottom profiles suggest differing transport modalities on the outer shelf in general a southern trough shaped region exhibits high terrigenous inputs and non steady state 210pb profiles whereas the northern basins contain steady state 210pb profiles and increased marine influence sediment gravity flows dominate accumulation in the southern region whereas within the northern portion surface plume sedimentation is indicated overall this study suggests that sediment gravity flows could be bypassing the northern basins perhaps a result of oceanographic influences and bathymetric steering as they seek a more direct route across the shelf

late quaternary sea level history of saipan commonwealth of the northern mariana islands usa a test of tectonic uplift and glacial isostatic adjustment models

knickpoint initiation and distribution within fluvial networks 236 waterfalls in the waipaoa river north island new zealand if knickpoints transmit signals of base level fall in river networks then improvements in our understanding of their retreat rate and basin wide distribution helps constrain the transient response following perturbation many studies of knickpoint retreat focus on the response of trunk streams to base level fall here we examine the response of an entire fluvial network as recorded by 236 active knickpoints distributed within the waipaoa river on the north island of new zealand base level fall within the waipaoa catchment initiated 18 000 years ago in response to a climatically triggered and tectonically exacerbated pulse of incision using observations from field work aerial photo analysis and a digital elevation model dem we study the knickpoint positions within the network we find that 70 of the knickpoints are located at drainage areas between 1 10 5 m 2 and 1 10 6 m 2 and more than half are b1 km upstream of a large change in drainage area for the knickpoints b1 km upstream of large tributary junctions we find that the retreat distances were well correlated with the tributaries drainage areas in order to determine how a pulse of incision distributes itself throughout a fluvial network we develop two simple end member models and compare their behavior to the observed knickpoint distribution in the waipaoa in the first model we propose that a knickpoint initiated at the basin outlet retreats upstream and distributes the signal throughout the network at a rate that is a power law function of drainage area in the second model we propose that knickpoints form near a threshold drainage area below which channels cannot incise with the same efficiency as possible in downstream reaches though neither model addresses the along stream variability in substrate or knickpoint form the misfit between the modeled and the observed knickpoints along stream positions are surprisingly low b1 km 1 25 of the total stream length for knickpoints with drainage areas b1 10 6 m 2 large misfits up to 3 5 km are observed for knickpoints with present day drainage areas greater than 1 10 6 m 2 the large single step in channel elevation that characterizes knickpoints presently observed in tributaries of the waipaoa river may not characterize the base level fall signal that propagated through the trunk streams evidence for progressive rather than instantaneous incision in the trunk streams the knickpoints vicinities to tributary junctions and the equivalent success of the two end member models lead us to conclude that the present positions of the 236 observed knickpoints are largely a consequence of thresholds in channel incision at low drainage areas

a spatially lumped model to investigate downstream sediment flux propagation within a fluvial catchment abstract a spatially lumped process response model pacmod is presented which calculates long time series 103 106 years of fluvial water discharge and sediment load at the river catchment outlet based on climatic data drainage basin characteristics and user defined parameters key aspects of the model are i the lumped approach allowing for fast simulations and preserving the same resolution from palaeoclimatic conditions and geomorphological reconstructions ii the parameterization of sediment routing and storage within the catchment pacmod was successfully tested on observed data from three present day fluvial systems the meuse the waipaoa and the po rivers moreover the simulated sediment flux for the meuse and for the waipaoa rivers in the late quaternary is in agreement with published field and modelling work pacmod experiments show how the downstream propagation of the original climatic signal is hampered by sediment routing and storage within the catchment

earthquakes as self organized critical phenomena a cellular automation model with threshold elements previously proposed by bak et al 1988 which generates 1 f noise and self organizes into a critical state is studied as a model for earthquake occurrence the model explains some of fractal features of earthquakes such as the power law distribution of the size of the earthquake the model is modified so that every earthquake may trigger aftershocks the modified trigger model explains other fractal features of earthquakes such as the power law decay of aftershock frequency and the power law decay of aftershock frequency and the power law correlation of the hypocenter distribution

quantifying temporal variations in landslide driven sediment production by reconstructing paleolandscapes using tephrochronology and lidar waipaoa river new zealand hillslope response to climate driven fluvial incision controls sediment export and relief generation in most mountainous settings following the shift to a warmer wetter climate after the last glacial maximum lgm 18 ka the waipaoa river new zealand rapidly incised up to 120 meters leaving perched low relief hillslopes unadjusted to that base level fall in the mangataikapua a 16 5 km2 tributary principally composed of weak melange pervasive post lgm landslides responded to 50 m of fluvial incision by sculpting and denuding 99 of the catchment by reconstructing lgm and younger paleosurfaces from tephra identified by electron microprobe analysis empa and lidar derived surface roughness we estimate the volume timing and distribution of hillslope destabilization in the mangataikapua and the relative contribution of landslide prone terrain to post lgm landscape evolution we calculate volume change between four paleosurfaces constrained by tephra age rerewhakaaitu 17 5 ka rotoma 9 4 ka whakatane 5 5 ka and waimihia 3 4 ka from the paleosurface reconstructions we calculate the total post lgm hillslope sediment contribution from the mangataikapua catchment to be 0 5 0 06 s d km3 which equates to a subcatchment averaged erosion rate of 1 6 mm yr 1 this is double the previous hillslope volume when normalized by study area demonstrating that landslide prone catchments disproportionately contribute to the terrestrial post lgm sediment budget finally we observe particularly rapid post waimihia erosion rates likely impacted by human settlement

hillslope response to climate modulated river incision in the waipaoa catchment east coast north island new zealand quantifying how hillslopes respond to river incision and climate change is fundamental to understanding the evolution of uplifting landscapes during glacial interglacial cycles we investigated the interplay among uplift river incision and hillslope response in the nonglacial waipaoa river catchment located in the exhumed inner forearc of an active subduction margin on the east coast of the north island of new zealand new high resolution topographic data sets light detection and ranging lidar and photogrammetry combined with field mapping and tephrochronology indicate that hillslopes adjusted to rapid latest pleistocene and holocene river incision through the initiation and reactivation of deep seated landslides in the erodible marine sedimentary rocks of the waipaoa sedimentary system postincision deep seated landslides can occupy over 30 of the surface area the ages of tephra cover beds identified by electron microprobe analysis on 80 tephra samples from 173 soil test pits and 64 soil auger sites show that 4000 5000 yr after the initiation of river incision widespread hillslope adjustment started between the deposition of the ca 14 000 cal yr b p waiohau tephra and the ca 9420 cal yr b p rotoma tephra tephrochronology and geomorphic mapping analysis indicate that river incision and deep seated landslide slope adjustment were synchronous between main stem rivers and headwater tributaries hillslope response in the catchment can include the entire slope measured from river to ridgeline and in some cases the interfluves between incising subcatchments have been dramatically modified through ridgeline retreat and or lowering using the results of our landform tephrochronology and geomorphic mapping we derive a conceptual time series of hillslope response to uplift and climate change induced river incision over the last glacial interglacial cycle

a 2400 yr record of natural events and anthropogenic impacts in intercorrelated terrestrial and marine sediment cores waipaoa sedimentary system new zealand the waipaoa sedimentary system spans 100 km from terrestrial upland to continental rise alluvial buffering has little effect on sediment flux at the outlet of this mesoscale dispersal system and hinterland to margin transport is accomplished rapidly because of this synergy the floodplain and shelf depocenters are sensitive to changes in sediment production in the hinterland and natural and anthropogenically forced changes in sediment source dynamics that occur at several temporal and spatial scales leave distinctive signals in the stratigraphic record manifested as variations in sediment properties these signals appear in intercorrelated sediment cores from a headwater riparian storage area and the major terrestrial and marine repositories for sediment discharged during the past 2 4 k y the signals represent the landscape response to vegetation and land use change short term fluctuations in climate that affect surface properties and processes and extreme storms and subduction thrust earthquakes extreme storms are the minimum geomorphologically effective event preserved in the sediment records lower magnitude storms that are integral components of the prevailing hydrometeorological regime create high frequency fluctuations in sediment properties and collectively contribute to event sequences of 100 yr duration events and event sequences comprise a hierarchy of temporally sensitive phenomena the impacts of which are conditioned by frequency and magnitude by contrast vegetation disturbance is a spatially sensitive phenomenon that directly impacts sediment source areas and lowers the threshold of landscape sensitivity to erosion for this reason the taupo eruption of 1 718 ka and the piecemeal vegetation changes that occurred after the arrival of polynesian settlers also generated strong depositional signals after european colonization deforestation of the hinterland altered landscape sensitivity and precipitated the transition to an erosional regime that impacted sediment production and dispersal across the entire magnitude frequency spectrum of events regulating sediment delivery to and transport in stream channels no other perturbation had such a profound impact on the late holocene depositional record

recent sedimentation patterns and facies distribution on the poverty shelf new zealand abstract modern sediment dispersal and accumulation on the poverty shelf off the waipaoa river new zealand is investigated using x radiographic radio isotopic and physical property analyses of nearly 200 box and kasten cores collected in january 2005 aboard the r v kilo moana the high yield small mountainous waipaoa river empties onto a tectonically active narrow margin and represents an important analog for shelf sedimentation in similar environments worldwide x radiographs and bulk density measurements from a multi sensor core logger show three distinct facies on the shelf where physical and or biological factors dominate strata formation spatial distribution of these facies delineates a radial pattern with distance from the river mouth from areas dominated by stratified layers on the inner shelf to mottled muds on the outer shelf demonstrating a continuum of controls from wave reworking to episodic and extreme wet event sedimentation despite a tectonic framework that supports rapid accumulation in two recently identified shelf depocenters analysis of short lived 7 be t 1 2 53 days reveals a broad spatial distribution across and along shelf in surface sediments suggesting rapid transport from the waipaoa source however beryllium 7 inventories are consistent with centennial scale trends observed by other researchers using longer lived 210 pb analyses with highest inventories in the shelf depocenters box core bulk density analyses show lower than average bulk densities within these depocenters and higher than average bulk densities on the inner shelf and between the depocenters these observations confirm rapid deposition of low density muds in the depocenters with higher bulk density possibly physically reworked sediments remaining off the mouth of poverty bay and between the depocenters based on this single observational period there appears to be no fundamental difference between seasonal and longer term accumulation patterns on the poverty shelf

earthquake prediction a critical review summary earthquake prediction research has been conducted for over 100 years with no obvious successes claims of breakthroughs have failed to withstand scrutiny extensive searches have failed to find reliable precursors theoretical work suggests that faulting is a non linear process which is highly sensitive to unmeasurably fine details of the state of the earth in a large volume not just in the immediate vicinity of the hypocentre any small earthquake thus has some probability of cascading into a large event reliable issuing of alarms of imminent large earthquakes appears to be effectively impossible key word earthquake prediction

holocene paleoseismicity in the fold and thrust belt of the hikurangi subduction zone eastern north island new zealand abstract along the 500 km long eastern coastline of the north island new zealand there are at most seven distinct holocene marine terraces aged 7 ka b p or less the highest of the terraces is 27 m above present day mean sea level the coastal region is subdivided into fourteen distinct subregions based on radiocarbon ages of marine deposits overlying wave cut shore platforms and geographic distribution of similarly aged terraces holocene marine terraces are the result of uplift associated with large earthquakes co seismic deformation this conclusion is based on characteristic stepped terrace morphology clustering of ages of terrace deposits within subrogions and the occurrence of co seismic uplift in historic time differential uplift across structures and distinct age variations at subregion boundaries are also characteristic recurrence intervals of uplift in any one terrace sequence vary from 0 4 ka to 2 0 ka and individual amounts of uplift vary from 1 0 m to 4 0 m in the past 2 5 ka ages from all terraces within subrogions indicate at least 21 paleoseismic events affecting coastal areas of eastern north island in that period these events cluster in time and in separate parts of eastern north island several earthquakes occurred 0 3 0 6 1 0 1 5 2 1 and 2 3 ka b p our data strongly support the concept of segmentation of deformation along the subduction margin the likely cause of coastal uplift is movement on steep reverse faults local structures rather than the subduction thrust that propagate from or near the subduction thrust some 20 25 km below the region earthquakes of moment magnitude 7 3 8 0 are estimated to be associated with these fault movements

last glacial maximum and hypsithermal in the southern hemisphere abstract a synthesis of the two contrasting climates of the upper quaternary in the southern hemisphere based on continental geological indicators suggests that the antarctic anticyclone is the most important climatic system in the hemisphere according to glaciological and oceanographic studies the antarctic anticyclone covered an area in the lgm that was double of that during the hypsithermal this phenomenon produced a consequent shifting of the climatic belts by approximately 10 of latitude to the north in the lgm and a migration to the south during the hypsithermal oceanic and continental anticyclones were active systems in shaping climates in south america australasia and southern africa these structures were enhanced throughout the lgm provoking generalized droughts and weakened at the hypsithermal permitting more rains in tropical latitudes the results presented here were obtained by integrating our own results with regional and continental syntheses of other authors the paleoclimatic proposals are amply validated by more than 1500 dates in the four continents geological and geomorphological features such as dunefields paleosols fluvial terraces and lake levels were the main tools employed in the work

holocene sediment deposition on the poverty slope margin by the muddy waipaoa river east coast new zealand the margin off the raukumara peninsula east coast north island of new zealand is characterised by high terrigenous sediment flux the dramatic effects of historic land use change the rapid uplift of mesozoic and soft tertiary sediments and by complex sediment tectonic interactions on a steep and unstable continental slope the poverty bay shelf and slope indentation are adjacent to the waipaoa river which delivers 15 mt year 1 of mud this study presents new data from the poverty slope the seaward extension of the waipaoa dispersal system a 3 km3 lobe of postglacial sediment emerges from the poverty gap and feathers down onto the upper slope downslope the poverty indentation has received a significant holocene flux of terrigenous sediment accumulating in two mid slope basins the paritu trough and a smaller lower slope basin below the south paritu ridge hemipelagic sediment has accumulated on the mid slope at around 0 05 g cm 2 year 1 0 06 cm year 1 since the mid late holocene seismic reflection echo type and backscatter imagery indicate mud deposits on the mid slope debris at the base of regularly spaced upper slope gullies and a large avalanche deposit in the upper paritu trough the consistency of the tephrostratigraphy indicates that despite slope instability hemipelagic sedimentation is the dominant background process operating at millennial time scales at least since the mid holocene the poverty slope should be included in any budget calculation of post colonisation increased sediment yield for the margin the poverty canyon has probably been largely inactive during the holocene highstand

coastal progradation and sediment partitioning in the holocene waipaoa sedimentary system new zealand abstract over the late holocene highstand the shoreline at poverty bay nz migrated 12 km seaward fed by sediment from the waipaoa river paleo shorelines indicate steadily decelerating progradation possibly signaling changes in forcing on the waipaoa sedimentary system to isolate the cause of this progradation slowdown we reconstruct late holocene tectonics and stratigraphy over the waipaoa coastal plain and nearshore from 7 ka present we find that decreasing rates of sediment storage by coastal progradation were driven by increasing tectonic storage in the steadily subsiding but rapidly growing coastal plain such that net terrestrial storage remained constant at 0 8 mt yr hence changes in shoreline migration were due to autogenic increases in accommodation rather than allogenic changes in forcing furthermore while the waipaoa sediment load is primarily mud reconstructions suggest that progradation was largely controlled by the supply of coarse grained sediment our results suggest that in coastal systems such as the waipaoa where progradation is confined and wave energy is high net accumulation of muds occurs only behind the prograding sandy shoreface which shelters them from wave attack accounting for mud storage in the waipaoa coastal plain and poverty bay suggests that export of muddy sediment to the waipaoa shelf remained roughly constant at 2 0 mt yr from 7 ka until the onset of anthropogenic deforestation in the 19th century

retrospective investigation of geomagnetic field time series during the 2009 l aquila seismic sequence abstract this paper reports the analyses of ulf ultra low frequency geomagnetic field observations coming from the geomagnetic observatory of l aquila during the period 2008 2009 this period includes the l aquila 2009 seismic sequence where the main shock of 6 april heavily damaged the medieval centre of the town and its surrounding area causing 308 deaths more than 1000 injuries and about 60 000 displaced people recently several publications have documented the observation of precursory signals which occurred before the 6 april earthquake e g eftaxias et al 2009 2010 while others do not find any pre earthquake anomaly e g villante et al 2010 di lorenzo et al 2011 in light of this the goal of this study is to carry out further retrospective investigations ulf magnetic field data are investigated by means of conventional analyses of magnetic polarization ratio improved magnetic polarization ratio and fractal analysis in addition total geomagnetic field data coming from the ingv central italy tectonomagnetic network have also been investigated using the simple inter station differentiation method within the limits of these methods no magnetic anomalous signal which may be reasonably characterized as a precursor of the l aquila earthquakes has been found

on the reported magnetic precursor of the 1989 loma prieta earthquake among the most frequently cited reports in the science of earthquake prediction is that by fraser smith et al 1990 and bernardi et al 1991 they found anomalous enhancement of magnetic field noise levels prior to the 18 october 1989 loma prieta earthquake in the ultra low frequency range 0 0110 10 001 hz from a ground based sensor at corralitos ca just 7 km from the earthquake epicenter in this analysis we re examine all of the available corralitos data 21 months from january 1989 to october 1990 and the logbook kept during this extended operational period we also examine 1 0 hz 1 s data collected from japan 0 0167 hz 1 min data collected from the fresno ca magnetic observatory and the global kp magnetic activity index the japanese data are of particular importance since their acquisition rate is sufficient to allow direct comparison with the lower frequency bands of the corralitos data we identify numerous problems in the corralitos data evident from both straightforward examination of the corralitos data on their own and by comparison with the japanese and fresno data sets the most notable problems are changes in the baseline noise levels occurring during both the reported precursory period and at other times long before and after the earthquake we conclude that the reported anomalous magnetic noise identified by fraser smith et al and bernardi et al is not related to the loma prieta earthquake but is an artifact of sensor system malfunction 2008 elsevier b v all rights reserved

postglacial after 18 ka deep sea sedimentation along the hikurangi subduction margin new zealand characterisation timing and origin of turbidites recent sedimentation along the hikurangi subduction margin off northeastern new zealand is investigated using a series of piston cores collected between 2003 and 2008 the active hikurangi margin lies along the pacific australia subduction plate boundary and contains a diverse range of geomorphologic settings slope basin stratigraphy is thick and complex resulting from sustained high rates of sedimentation from adjacent muddy rivers throughout the quaternary turbidites deposited since c 18 ka in the poverty ruatoria and matakaoa re entrants are central to this study in that they provide a detailed record of the past climatic conditions and tectonic activity here alternating hemipelagite turbidite debrite and tephra layers reflect distinctive depositional modes of marine sedimentation turbidity current debris flow and volcanic eruption respectively turbidites dominate the record ranging in lithofacies from muddy to sandy turbidites and include some basal reverse graded turbidites inferred to be derived from hyperpycnal flows stacked turbidites are common and indicate multiple gravity flows over short time periods the chronology of turbidites is determined by collating an extremely dense set of radiocarbon ages and dated tephra which facilitate sedimentation rate calculation and identification of the origin of turbidites sedimentation rates range from 285 cm ka during late glacial time 18 5 17 ka to 15 to 109 cm ka during postglacial time 17 0 ka turbidite deposition is controlled by 1 the emplacement of slope avalanches reorganising sediment pathways 2 the postglacial marine transgression leading to a five fold reduction in sediment supply to the slope due to disconnection of river mouths from the shelf edge and 3 the holocene pleistocene boundary climate warming resulting in a drastic decrease in the average turbidite grain size flood induced turbidites are scarce nine hyperpycnites are recognised since 18 ka and the youngest is correlated to the largest enso related storm event recorded onland lake tutira other turbidites contain a benthic foraminiferal assemblage which is strictly reworked from the upper slope and which relates to large earthquakes over the last c 7 ka they yield a shorter return time 270 430 years than the published coastal records for large earthquakes c 670 years but the offshore record is likely to be more complete the deep sea sedimentation along the new zealand active margin illustrates the complex interaction of tectonic and climate in turbidite generation climate warming and glacio eustatic fluctuations are well recorded at a millennial timescale 18 ka while tectonic deformation and earthquakes appear predominant in fostering turbidite production at a centennial timescale 270 430 years

results of ultra low frequency magnetic field measurements during the guam earthquake of 8 august 1993 we report the results of measurements of ultra low frequency magnetic noise during a large earthquake ms 7 1 at guam of 8 august 1993 depth 60 km the ulf observing system is located in the guam island about 65 km from the epicenter several distinct features of this analysis are summarized 1 we have proposed rather sophisticated statistical analyses monthly mean standard deviation in order to estimate the wave intensity and polarization i e ratio z h 2 a comparison between the ulf wave activity and kp is useful in distinguishing between the space geomagnetic pulsations and non space emissions 3 then the use of the ratio z h is found to be of essential importance in discrimating the emissions presumably of seismic origin from space plasma waves 4 the statistical analysis of the temporal evolution of this ratio has yielded that it shows a broad maximum only about one month before the earthquake and this suggests that the emissions during this period are very likely to be magnetic precursors 5 the temporal variation of z component is similar to that for the loma prieta earthquake such that it shows a broad maximum ten days two weeks before the earthquake and another increase a few days before the earthquake 6 the emissions presumably associated with the earthquake are of noise like nature and their main frequency is 0 02 0 05 hz with maximum intensity 0 1 nt

post last glacial maximum fluvial incision and sediment generation in the unglaciated waipaoa catchment north island new zealand abstract small river systems contribute a significant component of sediment delivered to oceans but the temporal evolution of fluvially eroded landscapes is needed a sequence of postglacial terraces in the unglaciated waipaoa river catchment provides the opportunity to document fluvial incision and sediment flux on an 2000 year timescale since the last glacial maximum lgm which has previously only been undertaken for the entire post lgm period this study also calculates sediment mass where previously sediment volume was calculated using a 15 m dem field mapping and surveying and tephrochronology we calculate rates of fluvial incision and sediment volumes excavated during successive age constrained postglacial incision events and correlate these with a framework of inferred climatic events established for new zealand we identify seven periods of terrace formation each succeeded by a period of fluvial incision six in total although the magnitude of the response during each incision event and thus the sediment volumes generated varied through time and across subcatchments draining two contrasting lithological terrains we conclude that incision events were essentially synchronous at least within the timeframe constrained by the ca 2000 year interval between successive eruptive airfall events slope relaxation processes were simultaneous with incision thereby indicating that both processes were likely climate driven we identify a period of accelerated fluvial incision 7 mm y 1 commencing before ca 14 0 cal ka bp during the early postglacial period and ceasing ca 7 9 cal ka bp toward the end of the early holocene warming period the magnitude of this incision response was significantly higher in subcatchments draining highly erodible lithologies in the higher uplifting parts of the catchment when river bedload was at over capacity in contrast within the remainder of subcatchments draining the more resistant lithologies and in areas of lower uplift and in parts subsiding incision and sediment generation was moderated by the presence of knickpoints overall since abandonment of the lgm to present day fluvial incision in the waipaoa and the adjacent waimata catchments generated 16 7 km3 of sediment of which 10 km3 90 of the estimated 35 mt of glacial postglacial slope and shelf sediment mass was potentially available for transport offshore of this 14 08 km3 7 4 km3 derived from upper and 6 7 km3 from remainder of subcatchments was excavated from waipaoa catchment at an average of 0 6 km3 ka 1 of which 80 was generated by ca 7 9 cal ka bp this potentially validates previous accounts of high rates of offshore sediment flux before 8000 14c ybp ca 8877 cal ybp thereafter for the period mid holocene cooling and variability mhcv ca 6 5 cal ka bp until the present day the rate of incision across all subcatchments slowed to 2 mm y 1 and generated just 20 of the total sediment volume in part this reflected a depletion of available sediment as rivers in the upper subcatchments returned to a steady state and coincidental with an increase in accommodation space in the rapidly growing coastal floodplain sediment flux to the marine depocentres was thereby limited

an examination of spatial variability in the timing and magnitude of holocene relative sea level changes in the new zealand archipelago holocene relative sea level rsl changes have been reconstructed for four regions within the new zealand archipelago the northern north island including northland auckland and the coromandel peninsula the southwest coast of the north island the canterbury coast south island and the otago coast south island in the north island the rsl highstand commenced c 8100 7240 cal yr bp when present mean sea level pmsl was first attained this is c 600 1400 years earlier than has been previously indicated for the new zealand region as a whole and is consistent with recent holocene rsl reconstructions from australia in north island locations the early holocene sea level highstand was quite pronounced with rsl up to 2 75 m higher than present in the south island the onset of highstand conditions was later with the first attainment of pmsl being between 7000 6400 cal yr bp in the mid holocene the northern north island experienced the largest sea level highstand with rsl up to 3 00 m higher than present this is demonstrably higher than the highstand recorded for the southwest north island and otago regions a number of different drivers operating at a range of scales may be responsible for the spatial and temporal variation in the timing and magnitude of rsl changes within the new zealand archipelago one possible mechanism is the north south gradient in rsl that would arise in the intermediate field around antarctica in response to the reduced gravitational attraction of the antarctic ice sheet ais as it lost mass during the holocene this gradient would be enhanced by the predicted deformation of the lithosphere in the intermediate field of the southern ocean around antarctica due to hydro isostatic loading and mass loss of the ais however no such long wavelength signals in sea surface height or solid earth deformation are evident in glacial isostatic adjustment gia model predictions for the new zealand region while research from australia has suggested that north south variations in holocene rsl changes due to hydro isostatic influences are limited or non existent at the regional to local scale post glacial meltwater loading on the continental shelf around new zealand is predicted by gia modelling to have a significant effect on the timing and magnitude of rsl changes through the phenomenon of continental levering the spatial variation in continental levering is controlled by the configuration of the coast and the width of the adjacent continental shelf with continental levering providing a robust explanation for the observed spatial and temporal variations in rsl changes further research is required to characterise the regional and local effects of different tectonic regimes wave climates and sediment regimes these are potentially very significant drivers of rsl variability at the regional to local scale however the magnitude of their potential effects remains equivocal

results of ulf magnetic field measurements near the epicenters of the spitak ms 6 9 and loma prieta ms 7 1 earthquakes comparative analysis the characteristics of the ulf magnetic field emissions measured at two magnetic observatories in the republic of georgia prior to and after the ms 6 9 earthquake that occurred near spitak armenia on december 7 1988 are compared with the apparently similar emissions associated with the ms 7 1 earthquake that occurred near loma prieta california on october 17 1989 the main features of the spitak measurements according to observations made at the dusheti station 128 km to the spitak epicenter as compared with the loma prieta measurements which were made at corralitos california 7 km to the loma prieta epicenter are the following 1 the intensity of ulf background activity started growing 3 to 5 days before the spitak earthquake whereas the corresponding increase in activity began 12 days before the loma prieta earthquake 2 a substantial ulf emission burst was recorded at dusheti starting 4 hours prior to the main shock a similar large burst of ulf activity commenced 3 hours before the loma prieta event and continued until the occurrence of the main shock 3 ulf activity remained high for about two weeks after the spitak earthquake and for several months after the loma prieta earthquake 4 ulf noise bursts were observed 1 to 6 hours before powerful aftershocks at spitak during the period of enhanced activity but there was no conclusive link between the ulf noise at corralitos and the after shocks a major difference in the ulf activity preceding the two earthquakes is a difference in amplitude 0 2 nt at spitak and 5 nt at loma prieta but this is easily explained as being caused by the different distances of the observation stations from the epicenters

residence time of alluvium in an aggrading fluvial system relationships between the surface area and age of alluvial deposits were used to estimate the residence time of alluvium in the 2205 km2 waipaoa river basin new zealand the contemporary waipaoa river is an efficient transporter of sediment to the continental shelf but the basin has been characterized by rapid channel and valley aggradation in the historic period and by extensive mid to late holocene alluvial storage in the lower reaches the area weighted mean age of alluvial deposits in the lower part of the river basin is 4400 yr these deposits comprise terrace remnants isolated by downcutting and holocene to recent sediments that are potentially remobilizable by the modern river even though the amount of storage is small relative to downstream transport the majority of the potentially remobilizable alluvium is likely to remain in storage for 100 yr and its half life time for 50 per cent removal is 2000 yr within the confines of the flfloodplain the apparent loss of older deposits is due primarily to burial but losses of the most recent deposits are due almost entirely to remobilization 30 40 per cent with the remainder preserved in the alluvial record for at least 104 yr most of this sediment is likely to remain in storage until there is a shift to a degradational state copyright 2006 john wiley sons ltd

last glacial aggradation and postglacial sediment production from the non glacial waipaoa and waimata catchments hikurangi margin north island new zealand abstract the sediment flux generated by postglacial channel incision has been calculated for the 2150 km 2 non glacial waipaoa catchment located on the tectonically active hikurangi margin eastern north island new zealand sediment production both at a sub catchment scale and for the waipaoa catchment as a whole was calculated by first using the tensioned spline method within arc map to create an approximation of the aggradational waipaoa 1 surface contemporaneous with the last glacial maximum and second using grid calculator functions in the gis to subtract the modern day surface from the waipaoa 1 surface the waipaoa 1 surface was mapped using stereo aerial photography and global positioning technology fixed the position of individual terrace remnants in the landscape the recent discovery of kawakawa tephra within waipaoa 1 aggradation gravels in this catchment demonstrates that aggradation was coincidental with or began before the deposition of this 22 600 14 c year old tephra and using the stratigraphic relationship of rerewhakaaitu tephra the end of aggradation is dated at ca 15 000 14 c years ca 18 000 cal years bp the construction of the waipaoa 1 terrace is considered to be synchronous and broadly correlated with aggradation elsewhere in the north island and northern south island indicating that aggradation ended at the same time over a wide area subsequent downcutting a manifestation of base level lowering following a switch to postglacial incision at the end of glacial age aggradation points to a significant southern hemisphere climatic warming occurring soon after ca 15 000 14 c years ca 18 000 cal years bp during the older dryas interval elevation differences between the waipaoa 1 c 15 ka terrace and the level of maximum channel incision i e before aggradation since the turn of the 20th century suggest about 50 of the topographic relief within headwater reaches of the waipaoa catchment has been formed in postglacial times the postglacial sediment flux generated by channel incision from waipaoa catchment is of the order of 9 5 km 3 of which 6 6 km 3 is stored within the confines of the poverty bay floodplain thus although the postglacial period represented a time of high terrigenous sediment generation and delivery only 30 of the sediment generated by channel incision from waipaoa catchment probably reached the marine shelf and slope of the hikurangi margin during this time the smaller adjacent waimata catchment probably contributed an additional 2 6 km 3 to the same depocentre to give a total postglacial sediment contribution to the shelf and beyond of 5 5 km 3 sediment generated by postglacial channel incision represents only 25 of the total sediment yield from this landscape with 75 of the estimated volume of the postglacial storage offshore probably derived from hillslope erosion processes following base level fall at times when sediment yield from these catchments exceeded storage

signature of pending earthquake from electromagnetic anomalies two electromagnetic em anomalies have been detected in the vlf frequency band before the athens earthquake eq mw 5 9 sept 7 1999 with the following characteristics i the first and second anomaly lasted for 12 and 17 hours respectively with a cessation of 12 hours ii the second anomaly ceased at about 9 hours before the eq iii the larger anomaly the second one contains approximately 80 of the total em energy received iv no em disturbance has been recorded in the vhf frequency band unlike with other cases e g the kozani grevena and egion eratini earthquakes the fault modeling of the athens eq based on information obtained by radar interferometry predicts two faults the main fault segment is responsible for 80 of the total energy released while the secondary fault segment for the remaining 20 moreover a recent seismic data analysis supports the hypothesis that a two event solution for the athens eq is more likely than a single event solution in addition the absence of surface rupture explains the absence of em detection in the vhf frequency band the present analysis reveals that the properties of the preseismic electromagnetic anomalies might be considered as signatures of a pending earthquake

tectonomagnetic field observations in central italy 1989 1995 abstract it has been reported that earthquakes and volcanic eruptions produce significant variations in the geomagnetic field to investigate possible tectonomagnetic effects related to seismic activity the istituto nazionale di geofisica installed a seismomagnetic network in central italy the area was selected after a magnetic noise survey geomagnetic field intensity data are simultaneously recorded at four magnetometer stations and at l aquila geomagnetic observatory which is located in the same area the data are differentiated in order to detect local magnetic field anomalies the present study reports geomagnetic field observations in central italy from july 1989 to march 1995 and also discusses the detectability of a tectonomagnetic effect in this area a variation of about 5 nt over a two month period january february 1990 has been observed in the geomagnetic field no other anomaly has been observed although moderate seismicity occurred in central italy during the study period

correlation of fluvial terraces within the hikurangi margin new zealand implications for climate and baselevel controls abstract a correlation of fluvial terraces is presented for eight non glacial catchments of the eastern north island new zealand within the actively uplifting hikurangi margin using a combination of loess and tephra coverbed stratigraphy and radiocarbon and osl dating of fluvial deposits and loess coverbeds we demonstrate correlation of four fill terraces t1 t4 the available age constraints suggest t1 15 30 ka t2 31 50 ka t3 50 70 ka and t4 115 ka but the association and temporal link with loess deposits suggest correlation with cold periods and thus the refinement of t2 late mis 3 31 40 ka t3 mis 4 55 70 ka t4 mi substage 5b 90 ka 5d 110 ka or mis 6 140 160 ka the ability to correlate terraces between catchments plus the lack of independent evidence for tectonic triggering events indicates terraces have probably formed in response to either climate terrestrial or baselevel sea level control climate control is indicated by the temporal link of post glacial incision with re establishment of forest cover and of lgm aggradation with limited grass and shrub cover and periglacial processes aggradation due to increased sediment supply under reduced vegetation is dramatically demonstrated by formation of the taupo pumice alluvium terrace in response to inundation by volcanic deposits unwelded ignimbrite following the 1 8 ka taupo eruption and the response to post settlement

age and height distribution of holocene transgressive deposits in eastern north island new zealand abstract holocene transgressive deposits are frequently exposed near the present day coastline of the study area along eastern north island new zealand they occur in sites of former estuaries that were filled during the postglacial rise in sea level we present one hundred radiocarbon dates of holocene transgressive deposits from the study area ranging in age from ca 10 000 to 5500 yr b p relative sea level curves up to ca 6000 yr b p were reconstructed for six locations the curves have similar slopes prior to about 7000 yr b p indicating that sea level rise was much more rapid than any tectonic uplift at that time the postglacial rise in sea level in new zealand is considered in general to have culminated at about 6500 yr b p but the upper limit ages of transgressive deposits in our study area vary from ca 5500 to 7000 yr b p at sites where the uplift rate is high the postglacial transgression culminated rather earlier than ca 6500 yr b p and at sites where there is subsidence or there is very low uplift the culmination is later than ca 6500 yr b p nine of fourteen dates from fossil trees in growth position that grew in and were buried by estuarine silt cluster in the age range ca 8000 8400 yr b p these data support the view that there was a minor regression or stillstand in the eustatic sea level rise at that time eleven tectonic subregions are recognized in the study area on the basis of average uplift rate most of these subregions coincide with those established from the number and ages of younger holocene marine terraces of probable coseismic origin

the influence of sea level and tectonics on late pleistocene through holocene sediment storage along the high sediment supply waipaoa continental shelf abstract we present geophysical and core evidence showing how subsidence caused by forearc shortening has accommodated late pleistocene and holocene sediments supplied to the tectonically active waipaoa shelf nz limiting off shelf export during the early sea level highstand the last glacioeustatic fall and subsequent rise exposed and then flooded a shelf segmented into subbasins separated by zones of uplift leaving key stratigraphic markers of shoreline regression and transgression that vary strongly in character across the shelf highstand sediment isopachs tied to piston cores dated using tephra correlation and a radiocarbon age model provide a sediment budget at 2000 yr intervals from the mid holocene 5500 cal yr bp to present sediment load estimates from our shelf budget are in agreement with published model estimates for suspended sediment discharge from the waipaoa river for the past 3000 yr but importantly do not show the 6 fold increase in the waipaoa s sediment output that began with human settlement 700 yr ago and accelerated with deforestation over the last century bypassing of waipaoa sediment to the slope may therefore be a recent phenomenon caused by unnaturally high sediment loads a conclusion supported by data reported elsewhere in this volume our study also reveals evidence for 1 a relatively thick mid shelf transgressive section deposited during the last eustatic rise that may correlate to estuarine sequences reported from numerous sites on the modern coastline of the north island 2 a slight decrease in total basin filling rates during the highstand and 3 variability in the partitioning of highstand sediments between individual subbasins that may reflect differing degrees of tectonic accommodation

coastal uplift mechanisms at pakarae river mouth constraints from a combined holocene fluvial and marine terrace dataset abstract one of the major environmental controls on sedimentary systems is tectonics and thus in order to make quantitative explanations and predictions of the behaviour of sedimentary systems it is important to quantify tectonic rates and mechanisms in this study we show how a combined holocene fluvial and marine terrace dataset can be used to place constraints on coastal uplift mechanisms at pakarae river mouth to the east of the waipaoa sedimentary system mapping and surveying of fluvial terraces shows that the terraces can be divided into three sets i pgt a fill terrace formed during post glacial sea level rise 10000 7000 cal yr bp ii a sequence of post 7000 cal yr bp degradation terraces and iii historical post ad 1880 flood terraces a conceptual model of terrace evolution proposes that coseismic uplift has resulted in the observed back tilting downstream divergence and successive abandonment of tectonic terraces coastal uplift mechanisms are then examined by comparing the fluvial and marine terrace uplift distribution and the uplift per event from the marine terraces with those predicted by forward elastic dislocation models the models agree with the interpretation that the terrace uplift can be explained by coseismic slip on a steeply west dipping reverse fault located close to the shore possibly in combination with rupture of the hikurangi margin subduction interface 10 24 km below this study also provides insights into the tectonic drivers and impacts on the adjacent waipaoa sedimentary system including the possible role of subduction earthquakes growth of structures on the shelf and upper slope and the role that the interplay between sea level and tectonic controls has on sediment dispersal

seismomagnetic effects from the long awaited 28 september 2004 m 6 0 parkfield earthquake precise measurements of local magnetic fields have been obtained with a differentially connected array of seven synchronized proton magnetometers located along 60 km of the locked to creeping transition region of the san andreas fault at parkfield california since 1976 the m 6 0 parkfield earthquake on 28 september 2004 occurred within this array and generated coseismic magnetic field changes of between 0 2 and 0 5 nt at five sites in the network no preseismic magnetic field changes exceeding background noise levels are apparent in the magnetic data during the month week and days before the earthquake or expected in light of the absence of measurable precursive deformation seismicity or pore pressure changes obser vations of electric and magnetic fields from 0 01 to 20 hz are also made at one site near the end of the earthquake rupture and corrected for common mode signals from the ionosphere magnetosphere using a second site some 115 km to the northwest along the fault these magnetic data show no indications of unusual noise before the earthquake in the ulf band 0 01 20 hz as suggested may have preceded the 1989 ml 7 1 loma prieta earthquake nor do we see electric field changes similar to those suggested to occur before earthquakes of this magnitude from data in greece uni form and variable slip piezomagnetic models of the earthquake derived from strain displacement and seismic data generate magnetic field perturbations that are con sistent with those observed by the magnetometer array a higher rate of longer term magnetic field change consistent with increased loading in the region is apparent since 1993 this accompanied an increased rate of secular shear strain observed on a two color edm network and a small network of borehole tensor strainmeters and increased seismicity dominated by three m 4 5 5 earthquakes roughly a year apart in 1992 1993 and 1994 models incorporating all of these data indicate increased slip at depth in the region and this may have played a role in the final occurrence of the 28 september 2004 m 6 0 parkfield earthquake the absence of electric and magnetic field precursors for this and other earthquakes with m 5 7 3 elsewhere in the san andreas fault system indicates useful prediction of damaging earthquakes seems unlikely using these electromagnetic data

a census of eddies observed in north atlantic sofar float data abstract sofar floats that looped in discrete eddies were studied in order to map and describe the distribution and characteristics of eddies in the north atlantic one hundred eighteen individual looping float trajectories loopers were identified each consisting of two or more consecutive loops each looper was interpreted to be in a discrete eddy and its characteristics were estimated from the float trajectory the highest percentage of loopers occured at 700m in the newfoundland basin where roughly half of the float data were in loopers mostly cyclones in the gulf stream region approximately 20 of the float data recorded at 700m were in loopers again mostly cyclones overall 21 of 700m data and 6 of 2000m data were in loopers the fastest swirl speeds 40cm s 1 were in cyclones south of the gulf stream most of which were in gulf stream rings but numerous swift 35cm s 1 anticyclones were found there too swirl velocity decreased with depth to roughly half as swift at 2000m as at 700m for three eddies in the sargasso sea measured simultaneously with floats at these two depths in the western north atlantic the average swirl velocity of cyclones and anticyclones was the same translation velocity of eddies was generally westward to southwestward at a few cm s 1 the mean translation velocity of 39 eddies in the sargasso sea was u bar 2 8 0 4 cm s 1 v bar 0 4 0 4 cm s 1 many of these were located just south of the gulf stream in the region of its recirculation and were probably advected by a westward current there near the gulf stream and along its extension in the newfoundland basin eddies were often advected downstream with speeds up to 15 20cm s 1 and eddy trajectories were often complicated south of 30 n and near the western boundary 700m eddies were advected northwestward and 1300m and 2000m eddies southeastward by boundary currents there numerous energetic anticyclones were observed south of the gulf stream one was tracked for 430 days and its properties well measured the formation of these eddies has not been documented but they are inferred to have formed near and by the gulf stream and to consist of a thick layer of 18 c water lying above a depression in the thermocline analogous anticyclones were observed in the newfoundland basin seaward of the gulf stream extension there

facies architecture morphostratigraphy and sedimentary evolution of a rapidly infilled holocene incised valley estuary the lower manawatu valley north island new zealand water well logs and vibracores recovered from the lower manawatu valley record the facies architecture morphostratigraphy and sedimentary evolution of this drowned river incised valley estuary over the past c 30 000 years the manawatu incised valley estuary was rapidly infilled during the holocene and as a result preserves a complete record of holocene estuary evolution the base of the holocene fill is marked by fluvial gravels deposited by the manawatu river during the lowstand of the last glacial maximum the gravels are overlain by back stepping transgressive fluvial silts and clays the transgressive fluvial unit is present only in the lower reaches of the valley due to accelerated sea level rise during the latter stages of the marine transgression large volumes of transgressive marine sediment were delivered to the mouth of the valley by rising sea levels during the early holocene forming a large subaqueous tidal delta this delta accreted and subsequently evolved to form a subaerial barrier in the mid holocene as sea levels stabilised during the sea level highstand the central basin of the estuary was rapidly infilled by marine and fluvial sediment and consequently lacks the mud facies characteristic of less rapidly evolved estuaries the transition from the sandy central basin estuarine environment to the overlying floodplain environment was extremely rapid in some locations in the valley the transitional fluvial bay head delta is missing completely while in most locations it is present only as a very thin deposit indicative of this rapid environmental transition infilling of the estuarine central basin was extremely rapid taking only 2000 2700 years the unique features of the manawatu estuary s evolutionary history are interpreted to primarily reflect the rapid infilling of the palaeo estuary driven by the high rates of sediment supplied to the valley from both marine and fluvial sources

the river it goes right on post glacial landscape evolution in the upper waipaoa river basin eastern north island new zealand abstract post glacial incision created 50 to 120 m of relief in the headwaters of the waipaoa river basin but it is not known how the signal of incision propagated along the trunk streams we addressed this issue by imposing previously determined long term rates of rock uplift that vary between 0 6 and 4 mm year 1 on the preaggradation longitudinal profile acting over the past 27 1 2 cal ka bp these rates are sufficient to passively elevate the waipaoa 1 terrace to its present level but during the last glacial maximum rates of vertical incision failed to match those of the uplifting rocks thus by the time favorable conditions for incision were reestablished after the antarctic cold new zealand late glacial reversal we estimate that the channel would have been elevated 55 m above the datum the river should otherwise have maintained the channel incised rapidly after the transition from glacial to interglacial conditions and reacquired its steady state form in the mid holocene 5 5 2 cal ka bp thereafter we suggest rates of incision matched rates of uplift no knickpoints are found on the upper waipaoa and mangatu rivers because incision commenced simultaneously along the entire length of the trunk streams and the pattern of incision is consistent with the downstream decline in the rate of rock uplift we also used hypsometric analysis to show how post glacial incision affected the surface morphology of low order 0 1 4 3 km 2 drainages in the headwaters of the waipaoa river basin values of the hypsometric integral are higher for proximal basins which the incision signal did not permeate than for low order basins bordering the upper waipaoa river and the lower reaches of tributaries that possessed enough erosive capacity to keep pace with incision along the mainstem hillslope adjustments were focused on the lower and mid sections of these basins so that the most pronounced changes to the hypsometric curve occur in the vicinity of the toe whereas the entire form of the hypsometric curve changes once mass wasting processes encroach onto hillslopes in the middle and upper sections of a basin

earthquakes can be stress forecast in 1997 geller et al wrote earthquakes cannot be predicted because scale invariance is ubiquitous in self organized critical systems and the earth is in a state of self organized criticality where small earthquakes have some probability of cascading into a large event physically however large earthquakes can only occur if there is sufficient stress energy available for release by the specific earthquake magnitude this stress dependence can be exploited for stress forecasting by using shear wave splitting to monitor stress accumulation in the rock mass surrounding impending earthquakes the technique is arguably successful but because of the assumed unpredictability requires explicit justification before it can be generally accepted avalanches are also phenomena with self organized criticality recent experimental observations of avalanches in 2 d piles of spherical beads show that natural physical phenomena with self organized criticality such as avalanches and earthquakes can be predicted the key to predicting both earthquakes and avalanches is monitoring the matrix material not monitoring impending source zones