Extreme Tsunami Research Articles

Tsunamis and Floods in Coos Bay Mythology

Tsunamis and Floods in Coos Bay Mythology byPatricia Whereat Phillips The principal evidence for major prehistoricearthquakes associatedwith subduction comes from investigations of estuarine marsh sediments buried by sand layers. These deposits suggest that portions ofthe coast subsided abruptly and were then overwashed by extreme tsunamis, or "tidal waves," that swept over the area and deposited the sand_ The number of these layers ... indicate that catastrophic earthquakes have occurred along the Northwest coast at least six times in the past 7,000 years, at intervals ranging from 300 to 600 years, with the last having occurred about 300 years ago. ? Paul Komar1 TSUNAMIS ARE TERRIFYING anddestructive events but relatively infre quent from the standpoint of a human lifetime. It isno wonder, then, that tsunamis appear in themythology of coastal peoples. To my knowledge, no one has looked in depth at a particular Oregon coastal people's language and theirmythology to assess the scope and effectof these events from the point of view ofNative people. Iwill focus on themythology of the Coos Bay Indians and on theHanis language (along with Milluk, itwas one of the two languages thatwas spoken on Coos Bay), as it is the one I am the most familiar with. Great Cascadia Earthquakes and Tsunamis 181 The linguistic data on this subject are unfortunately quite limited. The sole phrase recorded in theHanis language for earthquake is tVta lishtats. It translates literally as 'earth shaking', from tl'ta (or ti'da) for 'earth, land, ground' and the verb root lish- 'to shake, tomove'.2 Although there are a handful ofCoos texts thatmention tsunamis, there are none explicitly about earthquakes. In various interviews with ethnologists and linguists, however, some mention of earthquakes has been recorded. In a 1942 interview with linguist John P.Harrington, Hanis Coos informant John Waters said, "My [grandmother] toldwhen years ago therewas a big earthquake that caused cracks in the ground."3 In 1881, when George Bissell was working on a vocabu lary listwith an unidentified Lower Umpqua woman, he listed s? hwass as aword for earthquake and noted next to iton his schedule that "y?ohy for a caving in."4The woman volunteering 'caving in' along with 'earthquake' hints that she had heard accounts of earthquakes. Several words and phrases describe high and low tides, which is to be expected in the vocabulary of a coastal people. Iwas able to find only one word inHanis Coos that can be translated as 'flood', maatl, but therewas no further definition of the semantic domain for theword. The word was recorded only once, as the title of a tsunami story told by James Buchanan, from theHanis village Wu'allach (near Empire). Maatl probably refers to flooding in general and not specifically tsunamis. More often in theHanis language, phrases are used todescribe tsunamis, as 'when theflood time came therewas no ebb tide', 'now thewater rushed in',and 'thewater ran ashore far across the land'. Iwill consider these descriptions within the context of the narratives inwhich they appear. Althoughdozens ofCoos myths (bothin Hanis andMilluk) and other narratives have been recorded, they represent only a small portion of the narratives that have existed. Most of the narratives that have come down to us are primarily from twoHanis-speaking informants ? JimBuchanan, who worked principally with Henry Hull St. Clair and Leo Frachtenberg in the first decade of the twentieth century, and Annie Minor Peterson, who worked with Melville Jacobs in 1933and 1934.Annie Peterson, who was born on Coos Bay nearWu'laench (Cooston) but raised at theYachats reservation, also spoke Milluk, the language spoken at Cape Arago and South Slough on Coos Bay. The traditional narratives can be divided loosely between myths and historical narratives. Throughout the Northwest, Indians recognized this division of their stories. As Melville Jacobs noted, Long ago, [Franz] Boas and others pointed to the larger Pacific Northwest's natives own contrast of myths versus tales. Boas wrote correctly that this larger region s myths 182 OHQ vol. 108, no. 2 Courtesy ofCoos Historical andMaritimeMuseum, 995-D185 Coos elderAnnieMiner Peterson displays her traditional regalia and baskets in Empire,Oregon, in 1914. comprised recitalsofhappenings dated inan earlyerawhen things were ratherdiffer ent from what they were in the more recent era that...

Fast Modelling of Tsunami Wave Propagation using PC with Hardware Computer Code Acceleration

The field programmable gates array (FPGA) microchip is applied to achieve considerable performance gain in simulation of tsunami wave propagation using personal computer. The two-step Mac-Cormack scheme was used for approximation of the shallow water equations. An idea of PC-based tsunami wave propagation simulation is described. Comparison with the available analytic solutions and numerical results obtained with the reference code show that developed approach provides good accuracy in simulations. It takes less then 1 minute to compute 1 hour of the wave propagation in computational domain that contains 3000 × 2500 nodes. Using the nested greed approach, it is possible to decrease the size of space step from about 300 meters to 10 m. Using the proposed approach, the entire computational process (to calculate the wave propagation from the source area to the coast) takes about 2 min. As an example the distribution of maximal heights of tsunami wave along the coast of the Southern part of Japan is simulated. In particular, the interrelation between maximal wave heights and location of tsunami source is studied. Model sources of size 100 × 200 km have realistic parameters for this region. It was found that only selected parts of the entire coast line are exposed to tsunami wave with dangerous height. However, the occurrence of extreme tsunami wave heights at some of those areas can be attributed to the local bathymetry. The proposed hardware acceleration to compute tsunami wave propagation can be used for rapid (say, during few minutes) evaluation of danger from tsunami wave for a particular location of the coast

A Tsunami Risk Management Pilot Study in Heraklion, Crete

The area of northern Crete, South Aegean, Greece, has been struck by large tsunami waves in the past (e.g., 1650, 1956), and it is likely that similar tsunamis will occur in the future. A 6 km coastal segment to the west of Heraklion city, northern Crete, was selected for the development of a Tsunami Risk Management Pilot Study. The methodology applied incorporated three consecutive stages: (1) collection and analysis of data related to the physical planning, (2) semi-quantitative description of the potential impacts of a characteristic, extreme tsunami, (3) development of a series of approaches for taking prevention and mitigation measures. The steps taken in the three methodological stages were printed on a series of 12 thematic maps of 1 : 10,000 scale which included information about the geographic variation of (a) physical planning parameters describing the existing situation in the investigated area, (b) the characteristic tsunami features on land, and (c) the tsunami hazard impact and damage potential. Eventually the types of, and the locations where, various counter measures are required, were defined.

Bedrock-Sculpturing by Tsunami, South Coast New South Wales, Australia

Bedrock-sculpturing resulting in s-forms is associated with catastrophic flooding in near- and subglacial environments produced by flow velocities approximating . These velocities can also be produced by extreme tsunami generated by submarine landslides or comet impacts with oceans. Repetitive tsunami events during the late Holocene have overwashed headlands along the New South Wales south coast and produced two suites of bedrock-sculptured terrain. At the smaller scale, s-forms similar to muschelbrüche, v-shaped grooves, and sichelwannen have developed on upslopes while broad potholes, flutes, and transverse troughs have formed on headland crests. Cavitation features consisting of sinuous grooves, impact marks, drill holes, and cavettos appear more ubiquitously. At the larger scale stripped ramps, large potholes, cascade channels and canyon-like features have been generated. Six flow phenomena: Mach-stem waves, jetting, vortex impingement, horseshoe vortices, helical flow, and multiple vortex formation are all involved, either singly or in combination with each other, in the creation of bedrock-sculptured features and terrain. Tsunami-sculptured terrain undoubtedly has a global distribution whose extent requires further investigation.

Daily and seasonal sea-level oscillations on the Pacific coast of Canada : Waldichuk Michael, 1964. In: Studies on Oceanography dedicated to Professor Hidaka in Commemoration of his Sixtieth Birthday, 181–201

An Mw ≈ 8.1 earthquake south of the Samoan Islands on 29 September 2009 generated a tsunami that killed 189 people. From 4 to 11 October, an International Tsunami Survey Team surveyed the seven major islands of the Samoan archipelago. The team measured locally focused runup heights of 17 m at Poloa and inundation of more than 500 m at Pago Pago. A follow-up expedition from 23 to 28 November surveying the three main islands of Tonga's northernmost Niua group revealed surprising 22 m runup and 1 km inundation. We analyze the extreme tsunami runup and complex impact distribution based on physical and societal observations combined with numerical modeling. That an outer rise/outer trench slope (OR/OTS) event is responsible for a tsunami disaster in the Pacific calls for care in identifying and defining tsunami hazards. Evacuation exercises conducted in Samoa in the preceding year may have limited the human toll; however, cars were identified as potential death traps during tsunami evacuations. This event highlights the extreme hazards from near source tsunamis when the earthquake's shaking constitutes the de facto warning, and further underscores the importance of community based education and awareness programs as essential in saving lives.

Some characteristics of 25-cps. shallow-water ambient noise : Willis Jack and F.T. Dietz, 1965. J. acoust. Soc., Am., 37 (1): 125–130

An Mw ≈ 8.1 earthquake south of the Samoan Islands on 29 September 2009 generated a tsunami that killed 189 people. From 4 to 11 October, an International Tsunami Survey Team surveyed the seven major islands of the Samoan archipelago. The team measured locally focused runup heights of 17 m at Poloa and inundation of more than 500 m at Pago Pago. A follow-up expedition from 23 to 28 November surveying the three main islands of Tonga's northernmost Niua group revealed surprising 22 m runup and 1 km inundation. We analyze the extreme tsunami runup and complex impact distribution based on physical and societal observations combined with numerical modeling. That an outer rise/outer trench slope (OR/OTS) event is responsible for a tsunami disaster in the Pacific calls for care in identifying and defining tsunami hazards. Evacuation exercises conducted in Samoa in the preceding year may have limited the human toll; however, cars were identified as potential death traps during tsunami evacuations. This event highlights the extreme hazards from near source tsunamis when the earthquake's shaking constitutes the de facto warning, and further underscores the importance of community based education and awareness programs as essential in saving lives.