50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...

More documents

Recommendations

Info

shallow water, may be capable of generating damaging tsunami waves. Whilst there have been few studies to model landslide tsunami in New Zealand (e.g., Magill, 2001; Walters et al., submitted), NIWA is developing a growing database of submarine landslide distribution and geomorphologies derived from high-resolution multibeam bathymetry data. These data offer an opportunity to evaluate landslides as a potential source of tsunami waves. Studies by other workers (Watts et al., 2003) involving simple laboratory experiments of slope failure, derived empirical relationships between landslide geometry, water depth, various slope parameters, and the initial tsunami wave height generated from the draw down of the ocean surface over a submarine landslide failure. Whilst there are severe limitations in such an approach, and consequently very large uncertainties in the tsunami wave heights at the source, these relationships have been applied to real field examples on continental margins (e.g., McAdoo et al. 2000, McAdoo & Watts, 2004, de Lange & Moon, 2004). Although simplistic the approach offers a method of rapidly approximating the potential tsunami wave heights from a large landslide population. In this study we apply these empirical relationships to evaluate tsunami wave heights generated at the source of landslides, by analyzing the geomorphology of a subset of nearly 300 landslide failures recognised in Cook Strait and the Bay of Plenty. The landslides studied are from a wide range of water depths, from about 100 m to > 2000 m, and the majority has surface areas of < 5 km 2 . The method involves the measurement, within an ESRI ArcGIS framework, of a number of the landslide scar parameters from bathymetric DTMs, including maximum width, length, thickness via the head scarp height, slope angle, and water depth. The height of the initial tsunami waves were calculated using an empirical relationship developed for translational slides. The results of the calculations indicate initial drawdown tsunami wave heights of up to 6 m at the source of the landslides. Tsunami experts at NIWA suggest the uncertainties on the wave heights may be as much as a factor of three. In the absence of dating of individual landslides, we constructed relationships between frequency (annual rate of return) and initial wave height, by estimating a range of return times that might conceivably cover the entire populations studied. We correlated these relationships with an estimate of initial wave height for the giant Ruatoria Landslide, and we note differences between the Cook Strait and Bay of Plenty populations. Our study is strictly limited to the initial wave heights at the landslide sources and does not consider the propagation, amplification, and attenuation of the waves approaching the coast. POSTER TOWARDS A CLIMATE EVENT STRATIGRAPHY FOR NEW ZEALAND OVER THE PAST 30,000 YEARS D.J.A. Barrell 1 , B.V. Alloway 2 ,J.Shulmeister 3 , R.M. Newnham 4 and other contributors to the NZ-INTIMATE Project (P.C. Almond; P.C. Augustinus; N. Bertler; C. Briggs; L. Carter; C.H. Hendy; N.J. Litchfield; D.J. Lowe; B. Manighetti; M.S. McGlone; A.S. Palmer; H. Rother; P. Shane; R.P. Suggate; P.J. Tonkin; M.J. Vandergoes; P.W. Williams) 5 1 GNS Science, Private Bag 1930, Dunedin. 2 GNS Science, P.O. Box 30-368, Lower Hutt. 3 Department of Geological Sciences, University of Canterbury, Christchurch. 4 School of Geography, University of Plymouth, Plymouth PL4 8AA, United Kingdom. 5 Contact details of all authors can be found at www.paleoclimate.org.nz (d.barrell*gns.cri.nz) A poster summarizing representative evidence for environmental conditions and climate change in New Zealand during the past 30,000 years is an initial contribution to the INTIMATE (INTegration of Ice-core, MArine and TErrestrial records) initiative of the INQUA (International Union for Quaternary Research) Paleoclimate Commission. The aim of this international initiative is to improve knowledge of the nature, timing and regional-toglobal extent of climatic and environmental changes that have occurred since the Last Glaciation. The poster depicts key New Zealand onshore and offshore records that include the Last Glacial Maximum and/or the Last Glacial-Interglacial Transition from a variety of latitudes and elevations. Inset maps show New Zealand’s oceanographic setting, extent of glaciers, and distribution of vegetation zones at approximately 22,000 calendar years ago and at modern times (incorporating the inferred vegetation distribution at c. 1250 AD, before deforestation associated with human settlement). The calendar-age timescale is based on a combination of volcanic ash (tephra) and radiometric dates. Ice core records from Antarctica and Greenland are shown for comparison with New Zealand records. High-resolution records are derived from sedimentfilled volcanic craters in Auckland (total carbon, carbon isotopes and pollen), wetlands in northeast North Island, central North Island and western South Island (pollen), marine sediments off eastern North Island (oxygen isotopes), and stalagmites in caves in northwest South Island (carbon and oxygen isotopes). In addition, the poster includes a 50 th Kaikoura05 -4- Kaikoura 2005
ange of lower resolution or fragmentary records of climatic events, based on glacial landforms and deposits (central Southern Alps, South Island), river terraces and deposits, loess deposits (eastern North and South Islands), and aeolian quartz silt in nonquartzose, loess-like, andesitic tephric deposits of western North Island. The poster reflects work-in-progress and aims to assist comparison of the New Zealand paleoclimatic records with those from the wider Australasian region and elsewhere. The immediate goal is the establishment of an Australasian- INTIMATE climate event stratigraphy by the New Zealand and Australian paleoclimate communities, for presentation at the 2007 INQUA Cairns Symposium. POSTER LATE QUATERNARY DISPLACEMENTS ON THE WAITANGI FAULT, AVIEMORE DAM, SOUTH ISLAND, NEW ZEALAND D.J.A. Barrell 1 ,R.J.VanDissen 2 ,K.R. Berryman 2 & S.A.L. Read 2 1 GNS Science, Private Bag 1930, Dunedin. 2 GNS Science, P.O. Box 30-368, Lower Hutt. (d.barrell*gns.cri.nz) Aviemore Dam was constructed across the Waitaki River valley in the mid-1960s. The dam straddles the steeply WSW-dipping Waitangi Fault. At the time of construction, no evidence of late Quaternary movement was documented on the fault. However, in the mid-1990s, dam safety review investigations unearthed evidence of late Quaternary deformation, and this led to the detailed paleoseismological investigations that provided data for displacement characterisation of the fault and subsequent evaluations of dam safety under direct fault rupture loadings. The primary paleoseismology investigation method was the excavation of 10 trenches, the largest of which was up to 10 m deep and 180 m long, across faults and folds within 1 km of the dam, accompanied by geological mapping of surface exposures and landforms. Detailed logging of the trench walls (typically 1:20 scale) documented the geometry of Late Quaternary deposits and the locations, amount and sense of slip of the most recent fault displacements. Over 30 samples were dated to constrain the timing of past fault movements, using, where possible, at least two duplicate methods of luminescence, and complemented in a few instances by radiocarbon. The investigations documented two, and possibly three, surface rupture fault movements on the Waitangi Fault in the last c. 23,000 years, with the most recent movement between 13,100 and 14,100 years ago. These ruptures were located on, or up to 6 m west of, the bedrock fault that juxtaposes Mesozoic- and Tertiary-age rocks (respectively east and west of the fault). Relative upthrow has been to the west in the late Quaternary. This represents a reversal from a net westerly downthrow that accumulated during the late Tertiary as shown by the Mesozoic versus Tertiary rock relationships across the fault. The two most recent surface ruptures had singleevent, west-side-up, vertical separations of c. 0.5 m (penultimate) and c. 1.5 m (most recent). Slickenside-lineations, and other slip indicators, show an oblique right-lateral – reverse sense of late Quaternary rupture, with a horizontal (H) component greater than the vertical (V) component (ratios of displacement in the range of 1H:3V to 1H:1V). In addition, a zone of “small-scale” late Quaternary faults and folds, with single-event vertical separations of up to 0.7 m, extends up to at least 150 m west of the Waitangi Fault. The fault displacement characteristics documented from the field investigations were subsequently used to derive earthquake performance assessments for the dam, and to evaluate dam safety under direct fault rupture loadings. ORAL THE DEVELOPMENT OF ANTARCTIC GLACIAL HISTORY OVER THE LAST FIFTY YEARS P. J. Barrett Antarctic Research Centre, Victoria University of Wellington, P O Box 600, Wellington. (peter.barrett*vuw.ac.nz) Fifty years ago it was thought that the Northern Hemisphere had experienced 4 glacial episodes over the last two million years, and no-one supposed the Southern Hemisphere would be much different. That view was changed radically in 1973 with the first Antarctic offshore drilling by the Glomar Challenger in the Ross Sea. The cruise, which was led by Denny Hayes and Larry Frakes and included three New Zealanders, Derek Burns, Peter Webb and me, cored through glacial sediments that dated back 25 million years. The cruise that followed, Leg 29, led by Jim Kennett and Bob Houtz, cored a series of deep ocean sites to the north that covered the Cenozoic Era. This yielded the first oxygen isotope curve, from which they concluded there was Antarctic cooling and sea ice in the latest Eocene, and the formation of an ice sheet like today’s in the middle Miocene. The Leg 29 results could not, however, resolve the relative contributions of ice volume and temperature to the isotope signal, and gave no 50 th Kaikoura05 -5- Kaikoura 2005
Page 1 and 2: CHARACTERISATION OF NEW ZEALAND NEP
Page 3: myrtaceous. One 20 mm diameter flow
Page 7 and 8: CRETACEOUS-EOCENE TRANSGRESSION MAR
Page 9 and 10: consists of a well-developed canyon
Page 11 and 12: model. The relative position of the
Page 13 and 14: converts to plate theory. Thus, the
Page 15 and 16: and on the following morning the mi
Page 17 and 18: the LGM grass peak. This period of
Page 19 and 20: offshore west coast to offshore eas
Page 21 and 22: 4 Institut de Recherche pour le Dé
Page 23 and 24: VEGETATION AND CLIMATE CHANGE AT TH
Page 25 and 26: wider range. The youngest layer has
Page 27 and 28: few normal faults visible especiall
Page 29 and 30: TRACKING CRUSTAL DIFFERENTIATION AN
Page 31 and 32: EMPIRICAL SCALING RELATIONS FOR SEI
Page 33 and 34: hydrovolcanic eruptions then took p
Page 35 and 36: and that the MTL marks a Late Carbo
Page 37 and 38: faunal changes within these cores w
Page 39 and 40: material at subsurface depths of se
Page 41 and 42: survived through in low numbers in
Page 43 and 44: in the TVZ and southern Havre Troug
Page 45 and 46: Tephra beds are commonly used to ai
Page 47 and 48: The MCC is bounded by deep-seated t
Page 49 and 50: distal alluvial plains where large
Page 51 and 52: Many of the molluscs in the highly
Page 53 and 54: incremental slip history and paleoe
Page 55 and 56:
This paper explores what we know of
Page 57 and 58:
volcanism and a linear vent oriente
Page 59 and 60:
These areas are also described in
Page 61 and 62:
3D IMAGING OF THE FORE- AND BACKTHR
Page 63 and 64:
ascending methane fluids/gases of p
Page 65 and 66:
THE GRIFFENS ROAD TEPHRAS: VALUABLE
Page 67 and 68:
sideritic concretions that occur in
Page 69 and 70:
with 63.8%, and then [3] with 49.9%
Page 71 and 72:
U-Th-Ra disequilibria data. In part
Page 73 and 74:
landslide tsunami in the past. Rece
Page 75 and 76:
core complex mode, temperature driv
Page 77 and 78:
truncating three plutonic suites of
Page 79 and 80:
active, andesitic White Island volc
Page 81 and 82:
and voluminous than at any on Earth
Page 83 and 84:
oundaries and with immature source
Page 85 and 86:
The new era of commercial viability
Page 87 and 88:
TECTONICS OF THE GALATEA BASIN USIN
Page 89 and 90:
performed by the electron backscatt
Page 91 and 92:
25km northeast of the volcano. Alth
Page 93 and 94:
Most of the tectonic blocks in the
Page 95 and 96:
TECTONIC AND NON-TECTONIC CAUSES OF
Page 97 and 98:
The continental shelf of the Povert
Page 99 and 100:
5 Dept. of Mineral Sciences, Smiths
Page 101 and 102:
Adams CJ...........................
Page 103 and 104:
Naish T............................
show all

50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...

Create successful ePaper yourself

Delete template?

Save as template?