Tsunamis (eBook)

TABLE OF CONTENTS 6
PREFACE 8
1992-2002: PERSPECTIVE ON A DECADE OF POST-TSUNAMI SURVEYS 10
1. Introduction 10
2. Goals and Methods 12
3. Individual tsunami surveys 16
4. The use of regional run-up datasets as identifiers of tsunami sources 26
5. Extension to historical events: The case of the 1946 Aleutian tsunami 27
6. Conclusion 33
Acknowledgments 33
References 34
THE FIORDLAND EARTHQUAKE AND TSUNAMI, NEW ZEALAND, 21 AUGUST 2003 39
1 Introduction 39
2 Tectonic setting 41
3 Earthquake mechanism and deformation 41
4 Tsunami 44
5 Summary and Conclusions 49
Acknowledgements 50
References 50
TIMING AND SCALE OF TSUNAMIS CAUSED BY THE 1994 RABAUL ERUPTION, EAST NEW BRITAIN, PAPUA NEW GUINEA 51
1 Introduction 51
2 The 1994 Rabaul eruption and tsunamis 53
3 Tsunami deposits identified from Simpson Harbor 54
4 Lithofacies of tsunami deposits 55
5 Chronology of volcanic eruptions and tsunamis 58
6 Scale of the tsunamis 60
7 Discussion 62
8 Conclusion 63
Acknowledgements 63
References 63
ANALYSIS OF TIDE-GAUGE RECORDS OF THE 1883 KRAKATAU TSUNAMI 65
1 Introduction 65
2 Processing and Computing 68
3 Analysis of the tide-gauge records 72
4 Conclusion 84
Acknowledgement 84
References 85
MODEL OF TSUNAMI GENERATION BY COLLAPSE OF VOLCANIC ERUPTION: THE 1741 OSHIMA- OSHIMA TSUNAMI 86
1 Introduction 86
2 Laboratory Experiments 88
3 Improvement of two-layer Model 90
4 Reproducibility of the 1741 OSHIMA-OSHIMA tsunami 94
5 Conclusions 101
References 102
DELAYED PEAKS OF TSUNAMI WAVEFORMS AT MIYAKO FROM EARTHQUAKES EAST OFF HOKKAIDO 121
1 Introduction 121
2 The delayed peak generated in the sea area east off Hokkaido 122
3 Numerical calculations for The 1973 Nemuro-Hanto-oki earthquake tsunami 124
4 The delayed peak of the 1973 Earthquake in the numerically calculated results 129
5 Cause of the delayed peaks 130
6 The propagating routes of the delayed peaks 134
7 Generality of the delayed phase 136
8 Conclusions 137
Acknowledgement 138
Appendix: the transformation of the initial incident wave into the edge wave 138
References 140
FIELD SURVEY OF THE 2003 TOKACHI-OKI EARTHQUAKE TSUNAMI AND SIMULATION AT THE OOTSU HARBOR LOCATED AT THE PACIFIC COAST OF HOKKAIDO, JAPAN 141
1 Introduction 142
2. Tsunami run-up distribution 145
3 Numerical simulation of tsunami at the Ootsu harbor 152
4. Conclusions 154
Acknowledgements 162
References 162
VARIABILITY AMONG TSUNAMI SOURCES IN THE 17TH-21ST CENTURIES ALONG THE SOUTEHRN KURIL TRENCH 163
1 Introduction 164
2 2003 Tokachi-oki tsunami 165
3 Reanalysis of the 1952 tsunami 166
4 19th century earthquakes and their tsunamis 169
5 17th-century tsunami 170
6 Summary 174
References 175
HOLOCENE TSUNAMI TRACES ON KUNASHIR ISLAND, KURILE SUBDUCTION ZONE 177
1 Introduction 177
2 Material and methods 178
3 Results 182
4 Discussion 194
5 Conclusion 195
Acknowledgements 196
References 196
DISTRIBUTION OF CUMULATIVE TSUNAMI ENERGY FROM ALASKA-ALEUTIANS TO WESTERN CANADA 199
1 Introduction 199
2 Tsunami source areas 200
3 Distributions of square value of tsunami height 201
4 Historical tsunamis (1788-1899) 203
5 Distributions of cumulative tsunami energy 204
6 Conclusion 205
References 206
MAPPING THE POSSIBLE TSUNAMI HAZARD AS THE FIRST STEP TOWARDS A TSUNAMI RESISTANT COMMUNITY IN ESMERALDAS, ECUADOR 208
1 Introduction 208
2 Numerical modeling of the tsunami 210
3 Tsunami inundation map for Esmeraldas 216
4 Discussion and conclusions 219
Acknowledgements 219
References 220
PROGRESSES IN THE ASSESSMENT OF TSUNAMI GENESIS AND IMPACTS AROUND THE PORTUGUESE COASTS 221
1 Introduction 222
2 Earthquake and tsunami source 222
3 Tsunami modeling 230
4 Tsunami hazards 231
5 Conclusions 233
References 233
QUICK TSUNAMI FORECASTING BASED ON DATABASE 235
1 Introduction 235
2 Data base driven quick tsunami forecasting 236
3. Numerical Model 239
4. Quick tsunami forecasting of the 1983 tsunami event 242
5. Concluding remarks 243
Acknowledgements 244
References 244
ADJOINT INVERSION OF THE SOURCE PARAMETERS OF NEAR-SHORE TSUNAMIGENIC EARTHQUAKES 245
1 Introduction 245
2 Inversion method 246
3 Experimental setup 247
4 Slope effects 250
5 Source delimitation and spatially delimited inversion 251
6 Inversion in the Okada space 254
7 Conclusions 261
Acknowledgements 261
References 262
EXPERIMENTAL DESIGN FOR SOLID BLOCK AND GRANULAR SUBMARINE LANDSLIDES: A UNIFIED APPROACH 263
1 Introduction 264
2 Methods 268
3 Results 275
4 Concluding remarks 279
5 Acknowledgements 280
References 280
EFFECTS OF COASTAL FOREST ON TSUNAMI HAZARD MITIGATION – A PRELIMINARY INVESTIGATION 282
1 Introduction 282
2. Several reduction effects to tsunami disasters by coastal forest 283
3 Evaluation of the effect on tsunami reduction by using of numerical simulation 285
4 Conclusion 294
Acknowledgements 294
References 294
FLUID FORCE ON VEGETATION DUE TO TSUNAMI FLOW ON A SAND SPIT 296
1 Introduction 296
2 Experiments 297
3 Fluid force on vegetation 299
4 Discussions 302
5 Conclusions 306
References 307
HYDRO- ACOUSTIC MONITORING ON THE KAMCHATKA SHELF: A POSSIBILITY OF EARLY LOCATION OF OCEANIC EARTHQUAKE AND LOCAL TSUNAMI WARNING 308
1 Introduction 308
2 Hydro-acoustic data 310
3 Analysis of hydro-acoustic signals and Kamchatka Regional Earthquake Catalog 311
Date H Min. Sec. Lat. Long Dep. km Mb Source 317
4 Discussion 318
5 Conclusions 319
Acknowledgements. 320
References 320
ELECTROMAGNETIC TSUNAMI MONITORING: THEORY AND RECOMMENDATIONS 321
1 Introduction 321
2 Characteristics of the model medium and its seismic excitation 322
3 Equations of seismo-hydro-electromagnetic interaction 324
4 Early measurable signals of a seismic excitation of geological structures beneath a sea floor 327
5 Seismo-EM signals at the sea surface and in atmosphere 330
6 Discussion 334
7 Recommendations and conclusion 339
Acknowledgements 341
References 341
SUBJECT INDEX 343

HOLOCENE TSUNAMI TRACES ON KUNASHIR ISLAND, KURILE SUBDUCTION ZONE (p. 171-172)

A.YA. ILIEV1, V.M. KAISTRENKO1, E.V. GRETSKAYA1, E.A. TIKHONCHUK1, N.G. RAZJIGAEVA2, T.A. GREBENNIKOVA2, L.A. GANZEY2 AND A.A. KHARLAMOV3

1 Institute of Marine Geology and Geophysics FEB RAS, Yuzhno-Sakhalinsk, Russia
2 Pacific Institute of Geography FEB RAS, Vladivostok, Russia y
3 P.P. Shirshov Institute of Oceanology RAS, Moscow, Russia

The paper presents the detailed study of sediments deposited by middle-late Holocene tsunami in the Pacific Ocean at the Okhotsk Sea area and Izmena Bay coast of Kunashir Island. Seventeen thin sand-layers were found to be intercalated within peat of lacustrine deposits. Field data, grain-size composition, and biostratigraphical data allow interpretation of them as paleotsunami traces. Age of the sand-sheet was based a on radiocarbon dating and tephrostratigraphy. Diatoms helped identify the tsunami deposits’ origins and confirm that the sands had a marine source, and establish the landward extent of tsunami inundation. Tsunami deposits contain more contents of neritic and oceanic diatoms than marine units deposited during Holocene transgressions. The sand layers were deposited by tsunami with a maximal run-up more than 7 m, and penetration inland more the 2.5 km. The time period relating to the found tsunami deposits is 6,000–7,000 years. Correlation of tsunami events of Kunashir, Iturup Island, and Eastern Hokkaido have been done.

Key words:
tsunami deposits, diatoms, inundation limit, Holocene, Southern Kuriles.

1 Introduction

Located in one of the most active seismic regions of North-Western Pacific, Kunashir Island is known to have several great earthquakes during historical times, some of which were accompanied by tsunami. Tsunami waves produced by the 4 October 1994 earthquake, the epicenter of which was located near Shikotan Island, had the heights up to 8.7 m above mean sea level on the eastern coast of the Kunashir Island (Korolyov et al., 1997). Catastrophic tsunami are rare events, and historical data does not include reliable estimates of their frequency, impact on natural environments, and their effect on coastal development and tsunami hazard prognoses. The modern approach to such problems supposes a search and analysis of geological traces of paleotsumani that allows a reconstruction of the chronology of catastrophic tsunami at the Holocene, estimate their frequency and intensity, and spatial distribution on the basis of the correlation of tsunami deposits of contiguous areas. Evidence of strong tsunamis and pre-historic earthquakes in this region has been found in Iturup Island (Bulgakov et al., 1995) and Eastern Hokkaido (Nanayama et al., 2000, 2003, Sawai, 2002, Hirakawa et al., 2003).

Existing tsunami catalogues contain the tsunami data for the Kunashir Island coast only since 1958. Such a short tsunami history of this region doesn’t allow the creation of a good model for the description of the tsunami activity. However the needed tsunami data can be found in Holocene coastal sequences. Holocene peatlands, widespread along the Pacific coast of Kunashir and within low isthmuses are informative objects for paleotsunami study. Other useful objects for examination are numerous modern, and ancient, coastal lakes in the region. The paleotsunami study includes searches of their traces in Holocene sequences and, afterwards, the identification of their origins by diatom analysis and sedimentological methods.

Diatoms are particularly useful in studies of paleotsunami deposits because different species are found in freshwater than in brackish-marine environments, and, therefore, can be used to identify past marine incursion, including those associated with tsunami (Minoura and Nakata, 1994, Hemphill-Haley, 1996, Nanayama et al., 2000, 2003, Nishimura et al., 2000, Sawai, 2002). Frequent volcanic activity on Kunashir Island are main factors for favorable diatoms development in different freshwater and marine environments (Grebennikova, 2000). The presence of marine and brackish diatoms among freshwater assemblages in thin sand layers indicates short-time marine influence, which can be connected to storm-surge or tsunami. Marine diatoms from these deposits are rare and most valves are fragmented (Sawai, 2001, 2002). Diatom assemblages from marine deposits that formed during transgressions are characterized by high abundance and high diversity of marine species and well-preserved valves. Ecological parameters of such diatom assemblages are typical for climatic warming. Thickness of transgressive sequences is, as a rule, significant. This paper presents the result of reconnaissance work, some stratigraphical data, and other evidence, for a several tsunami that occurred about 6,000-7,000 years BP on the South Kurile region.