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Item Community preparedness for volcanic hazards at Mount Rainier, USA(BioMed Central Ltd, 2021-12-09) Vinnell L; Hudson-Doyle EE; Johnston DM; Becker JS; Kaiser L; Lindell MK; Bostrom A; Gregg C; Dixon M; Terbush BLahars pose a significant risk to communities, particularly those living near snow-capped volcanoes. Flows of mud and debris, typically but not necessarily triggered by volcanic activity, can have huge impacts, such as those seen at Nevado Del Ruiz, Colombia, in 1985 which led to the loss of over 23,000 lives and destroyed an entire town. We surveyed communities around Mount Rainier, Washington, United States, where over 150,000 people are at risk from lahar impacts. We explored how factors including demographics, social effects such as perceptions of community preparedness, evacuation drills, and cognitive factors such as risk perception and self-efficacy relate to preparedness when living within or nearby a volcanic hazard zone. Key findings include: women have stronger intentions to prepare but see themselves as less prepared than men; those who neither live nor work in a lahar hazard zone were more likely to have an emergency kit and to see themselves as more prepared; those who will need help to evacuate see the risk as lower but feel less prepared; those who think their community and officials are more prepared feel more prepared themselves; and benefits of evacuation drills and testing evacuation routes including stronger intentions to evacuate using an encouraged method and higher self-efficacy. We make a number of recommendations based on these findings including the critical practice of regular evacuation drills and the importance of ongoing messaging that focuses on appropriate ways to evacuate as well as the careful recommendation for residents to identify alternative unofficial evacuation routes.Item Organisational response to the 2007 Ruapehu Crater Lake breakout lahar in New Zealand: Use of communication in creating an effective response(Springer International Publishing, 2016-01-05) Becker J; Leonard GJ; Potter SH; Coomer MA; Paton D; Wright K; Johnston DM; Fearnley, C; Bird, D; Jolly, GE; Haynes, KWhen Mt. Ruapehu erupted in 1995-1996 in New Zealand, a tephra barrier was created alongside Crater Lake on the top of Mt. Ruapehu. This barrier acted as a dam, with Crater Lake rising behind it over time. In 2007 the lake breached the dam and a lahar occurred down the Whangaehu Valley and across the volcano’s broad alluvial ring-plain. Given the lahar history from Ruapehu, the risk from the 2007 event was identified beforehand and steps taken to reduce the risks to life and infrastructure. An early warning system was set up to notify when the dam had broken and the lahar had occurred. Physical works to mitigate the risk were put in place. A planning group was also formed and emergency management plans were put in place to respond to the risk. To assess the effectiveness of planning for and responding to the lahar, semi-structured interviews were undertaken with personnel from key organisations both before and after the lahar event. This chapter discusses the findings from the interviews in the context of communications, and highlights how good communications contributed to an effective emergency management response. As the potential for a lahar was identifiable, approximately 10 years of lead-up time was available to install warning system hardware, implement physical mitigation measures, create emergency management plans, and practice exercises for the lahar. The planning and exercising developed effective internal communications, engendered relationships, and moved individuals towards a shared mental model of how a respond to the event. Consequently, the response played out largely as planned with only minor communication issues occurring on the day of the lahar. The minor communication issues were due to strong personal connections leading to at least one case of the plan being bypassed. Communication levels during the lahar event itself were also different from that experienced in exercises, and in some instances communications were seen to increase almost three-fold. This increase in level of communication, led to some difficulty in getting through to the main Incident Control Point. A final thought regarding public communications prior to the event was that more effort could have been given to developing and integrating public information about the lahar, to allow for ease of understanding about the event and integration of information across agencies.Item The late quaternary cover bed stratigraphy and tephrochronology of north-eastern and central Taranaki, New Zealand : a thesis presented in partial fulfullment of the requirements for the degree of Doctor of philosophy in soil science at Massey University, Palmerston North, New Zealand(Massey University, 1989) Alloway, Brent VictorThis study involved the recognition and description of tephra, lahar and debris avalanche deposits generated from activity centred at Egmont Volcano over the last c.l30kyrs B.P. Stratigraphic relationships between the various cover bed deposits of north-eastern and central Taranaki are discussed and their distributions mapped where possible. The stratigraphic record indicates that tephra emission and lahar inundation are typical, recurring features of Egmont Volcano. Average periodicity for moderate to major sized eruptions (>107m3) may be as frequent as, one every 250 years. Tephras from Egmont Volcano have been correlated to both the adjacent Wanganui and Waikato districts. Six rhyolitic tephras erupted from the Central North Island have been identified in Taranaki and are especially valuable as widespread time planes within the andesitic cover bed succession. At least thirteen lahars are shown to have been deposited over extensive areas of the ring plain during the last 22.5 kyrs B.P. Many of these lahars became channelised within stream and river catchments to extend to the North Taranaki coastline. Partial or complete collapse of Egmont Volcano at c.23kyrs and much earlier at c.100kyrs B.P. generated large volumed, debris avalanches that spread principally over a wide north-eastern to south-eastern arc. The resulting deposits are characterised by extensive areas of mounds now deeply buried by a younger late Pleistocene and Holocene tephra mantle. The stratigraphy of an alternating sequence of reddish (S-units) and yellowish (L-units) medial beds was also investigated. Generally their thinning pattern is similar to that of coarse ash and lapilli suggesting tephric origin.The thinning pattern of L-units however, is occasionally interrupted by localised overthickening and indicates localised aeolian deposition during cool to cold climatic periods. The biostratigraphic record constructed from pollen examinations support the climatic interpretations made from the medial stratigraphy. The measurement of quartz content in medial units is shown to be a particularly useful parameter for assessing past climatic conditions. Two peaks in quartz influx were recorded and correlated to the full-glacial periods of oxygen isotope stages 2 and 4. Forming the North Taranaki coastal plain are five uplifted marine terraces, that provide a c.0.45 Ma record of successive sea level oscillations with moderate to low rates of crustal deformation. The present extent of these terraces is related to lahar deposits within their cover beds which have repeatedly advanced the coastline and retarded coastal erosion.Item Geophysical investigation into the internal dynamics of moving lahars : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Earth Science at Massey University, Palmerston North, New Zealand(Massey University, 2011) Cole, Susan ElizabethLahars and other mass flows are highly hazardous phenomena that can pose great risk to areas in their path. Due to their often unpredictable onsets, scientific observations are limited. In addition, the erosive capabilities of a lahar mean that the most commonly used monitoring and sampling methods, such as load cells and bedload traps, are often damaged early in the flow. The cost of repair and maintenance of these instrumentation prohibits comprehensive coverage of each channel that might be at risk from lahars. The development of seismic sensors as an alternative monitoring method could prove effective as they do not require contact with a flow and are therefore less at risk from damage. The complex behaviour of a lahar can be witnessed in the geophysical record of its passage which, in combination with more traditional monitoring methods, can be used to record the detailed evolution of a flow. The three-dimensional analysis of seismometer recordings can provide an approximation of the frontal velocity that may differ from maximum velocity estimates made using super-elevation calculations. Comparisons of the seismic records of different mass flow types illustrate that it is possible to differentiate between them. Frequency analysis allows for the distinction of the flow mechanisms, particle interactions, and dominant rheology of a lahar. Low frequencies are more indicative of bedload frictional motion, while higher frequencies reflect the collisional impacts of particles, either between themselves or with the substrate. Detailed records of a flow at a single site provide a comprehensive understanding of the temporal variations that occur within the duration of a lahar, while comparative analyses of numerous sites along a channel highlight its downstream evolution. While initial onset signals can be recorded at local-to-source sites, they are attenuated too quickly to be observed further downstream. The records at proximal sites can, however, reflect the stages, or packets, involved during the main bulk of lahar initiation. At more distal sites, observations show that a lahar transitions to a [minimal] 4-phase behaviour. This consists of a frontal bow wave of ambient streamwater that increases in volume with distance from source, and immediately precedes the lahar proper. The following phases are defined by variations in sediment concentration, velocity, stage, and, in the case of Crater Lake-originating lahars, water chemistry. The understanding of the variable behaviour possible during a lahar, as well as the identification of the specific flow type recorded, is fundamental to modelling approximations of flow volumes, sediment concentrations, likely inundation areas, and probable damage by the flow. It is essential for the development of future warning systems that the variations that can occur within a single lahar are better understood, as lahars represent a serious threat to the slopes of many volcanoes worldwide.Item Late quaternary lahars from Mount Ruapehu in the Whangaehu River, North Island, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosoophy in Soil Science at Massey University(Massey University, 1993) Hodgson, Katherine AnneThe stratigraphic record of lahars in the Whangaehu River reveals that in the past 180,000 years this route has been one of the main conduits for lahars from Mount Ruapehu, the highest active andesitic stratovolcano in the Central North Island of New Zealand. Both debris flows and hyperconcentrated flows have engulfed surfaces up to 160 km distance from the Volcano. Eight episodes of laharic activity are recognized by the distinctive lithology and similar age of their deposits. The newly defined upper Pleistocene Whangaehu Formation provides evidence for the earliest lahar event in the Valley, c. 180,000- 140,000 years ago. There is only meagre evidence for laharic activity following this event until the Ohakean and Holocene, although two new informally named deposits - the Mangatipona pumice sand (c. 37,000 years B.P.) and Apitian lahars (c. 32,000-25,500 years B.P) - are recognized, of minor extent. The formerly defined late Quaternary Te Heuheu (c. 25,500- 14,700 years B.P.), Tangatu (c. 14,700-5,370 years B.P.), Manutahi (c. 5 ,370-3,4600 years B.P.), Mangaio (c. 4,600 years B.P.) and Onetapu (< c. 1,850 years B.P.) Formations are here described and interpreted. Triggering mechanisms for lahar deposits are distinguished based on lithological criteria. (a) Bouldery deposits in the Whangaehu Formation are interpreted to have been emplaced by a single highly competent debris flow triggered by a southerly-directed flank collapse at Mount Ruapehu. This debris flow was competent enough to transport boulders up to 2 m in diameter over 140 km from the Volcano. Bouldery deposits are also recognized in the Onetapu Formation, but are restricted to higher gradient surfaces on the Mount Ruapehu ring plain. The Onetapu Formation deposits are interpreted to have been emplaced by lahars resulting from catastrophic drainage of Crater Lake, which occupies the active crater on Mount Ruapehu. (b) Pebbly and sandy deposits are interpreted to have been emplaced by low competence debris flows and hyperconcentrated flows. These lahar deposits are recognized in all formations described. The lithology in these deposits is commonly pumice and they are interpreted to have been triggered by eruptions and/or high rainfall events at the Volcano. Formations, and individual members within Formations, were dated by radiocarbon dating of organic material found below, within or above lahar deposits, or by coverbed stratigraphy. Both rhyolitic and andesitic tephras provided recognizable time planes in the late Quaternary coverbeds overlying lahar deposits. In this study quantitative analysis of quartz abundance, which is shown to vary between loesses and palaeosols, is used as an indirect means of establishing a surrogate for past climate changes which have been correlated to the deep sea oxygen isotope curve. A minimum age for the newly defined Whangaehu Formation is established by this method. The accumulation rate for lahars in the Whangaehu River has accelerated from 1 km3 every c. 23,000 years in the past c. 160,000 years to 1 km3 in 589 years in the past c. 2,000 years. This acceleration probably results from the increased frequency of lahars in the River following the development of Crater Lake c. 2,000 years B.P. According to this pattern an estimated 0.17 km3 volume of lahars could be anticipated over the next 100 years. If the 2,000 year accumulation rate were to be met over the next 100 years there would be 170 lahars of l0[superscript]6 m3 in this time interval , or 17 lahars of 10[superscript]7 m3 (or 1.7 lahars of 10[superscript]8 m3). The largest reported volume for an historic lahar is 10[superscript]6 m3 and these have occurred on average once every 30 years. The accumulation rate for historic lahars is 0.0054 km3 in 100 years. Therefore, although the accumulation rate appears to have slowed down, further large lahars with magnitudes 10 or 100 times greater than those witnessed could be expected.Item The clockwork lahar : examining issues management in a New Zealand public service context : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Management in Communication Management at Massey University, Palmerston North, New Zealand(Massey University, 2008) Dittmer, David MarkIssues management has been practised over the past 30 years. However, the literature has focused on how corporations manage issues, while public service organisations have been ignored. This study looked at the issues management of a tephra dam-break lahar from 1996-2007 on Mount Ruapehu, New Zealand by a group of public service organisations. 19 interviews were conducted with people involved with the management of the ‘lahar issue’ to find out how the issue was managed. Further a content analysis of 309 articles from five newspapers, spanning the full eleven year period, was conducted to examine the salience (attention) given to the issue, the frames commonly used to present the issue and the sources who ‘drove’ the issue. The data from the content analysis was interpreted to create a five-stage lifecycle of the ‘lahar issue’. Further, data from the interviews was compared with a summary process of the issue management process. This comparison showed that five issues management process stages were employed to manage the ‘lahar issue’ although they were not referred to as such. Initially, the Department of Conservation consulted stakeholders during the development of options to deal with the lahar (1996-1999). Later in the lahar’s management, lahar stakeholders fell into two categories: internal - those involved with the mitigation and response - and external - the public. Internal stakeholders were communicated with through meetings and email. External stakeholders were communicated with through local media, presentations and meetings. Overall, it was concluded that media gave substantial attention to the lahar issue over the eleven year period. Some of those involved with managing the ‘lahar issue’ were able to identify the phases of media coverage. Further, this study identified ten frames that media employed when reporting the lahar. The most-frequently used frames were those focusing on the response (lahar response), describing the lahar (diagnosing causes of problem(s)) and discussing the potential impacts from a lahar (definition of problem(s)). Department of Conservation Scientist, Dr Harry Keys, was shown to be a primary definer – an influential source. The results suggest he defined coverage because of his status as both an official source, due to the organisation he was associated with, and also as an authoritative source due to his role as a scientist. Further, he was regularly drawn upon as a source over the entire period of the ‘lahar issue’ coverage.Item Robbanásos kitörés az éj leplealatt (A tudomány új eredményei - első kézből).(Massey University., 2007-01-01) Nemeth, KarolyNo abstract availableItem Exploding lakes in Vanuatu: ''Surtseyan-style'' eruptions witnessed on Ambae Island(International Union of Geological Sciences, 2006) Nemeth K; Cronin SJ; Charley D; Harrison M; Garae EAfter a long silence, Lake Vui on Ambae Island burst into spectacular life on November 28, 2005, disrupting the lives of the 10,000 inhabitants on this sleepy tropical island the SW Pacific. "Surtseyan-style" explosions burst through the Island's summit lake waters, forming a new tuff-cone, and threatening to form deadly lahars or volcanic floods. Such eruptions are rarely well observed, and these fleeting opportunities provide a chance to match volcanic processes with rock-sequences common in the geologic record...