共查询到20条相似文献，搜索用时 31 毫秒
1.
This study analyzes fatalities caused by rip currents in important locations along east and west coasts of India for the period 2000–2010. Results include the frequency of fatalities from rip currents, their cause, and their spatial distributions. Rip current fatalities are most common in the southeastern India, with a non-uniform spatial distribution. August and October are identified as most favorable for rip current generation. In India, rip current-related drowning is estimated as 39 per year during the last decade. East coast of India averaged 30–40 drownings, and west coast of India averaged 5–10 drownings per year. In coastal Andhra Pradesh, more than 350 people had been drowned due to rip currents and only 10 people were rescued. Visakhapatnam recorded highest drowning (293); R. K. beach is the most vulnerable potential rip current zones. From 2007 onward, rip current deaths increased at an alarming rate. The frequency of rip current drownings increased markedly during shore-normal wave incidence and mid-low tidal stages. A new empirical forecasting technique has been developed for prediction of rip current risk in India for the first time. FORTRAN-based software was developed to generate automatic rip current forecast report for any given location. The scale’s performance was tested with field data and by using different statistical methods. The new predictive scale is predicting rip current occurrences reasonably well. 相似文献
2.
A database was compiled for the period 1977–2007 to assess the threat to life in the conterminous United States from nontornadic
convective wind events. This study reveals the number of fatalities from these wind storms, their causes, and their unique
spatial distributions. Nontornadic convective wind fatalities occur most frequently outdoors, in vehicles including aircraft,
or while boating. Fatalities are most common in the Great Lakes and Northeast, with fewer fatalities observed in the central
United States despite the climatological peak in severe thunderstorms in this region. Differences in fatality locations between
tornadoes and nontornadic convective wind events highlight the unique combination of physical and social vulnerabilities involved
in these deaths. Understanding these vulnerabilities is important to future reduction of nontornadic convective wind fatalities. 相似文献
3.
Quasi-permanent rip current hot spots at Pensacola Beach, Florida, pose a significant hazard to beach users, largely because the hot spots are located at or close to the primary access points. While an increase in the number of lifeguards has led to a decrease in the number of drownings since 2004, the number of rescues and contacts has increased to over a 30,000 year. Despite warning signs at access points along the beach, it is not clear whether beach users are able to identify a rip channel or an active rip current. To assess beach users’ knowledge of rip currents and their ability to identify rip channels and currents, 97 surveys were conducted between June and September of 2010 at Pensacola Beach. Beach users were asked to identify rip channels in oblique photographs taken on green, yellow and red flag days when the potential for rip currents is low, medium and high, respectively. A majority of participants suggested that they could identify a rip channel or current (if present), but less than 20 % of beach users were able to identify the rip channels and currents. The majority of participants identified heavy surf areas as the location of the rips versus the relatively flat water of the current or the darker color water of the channel. Results further suggest that most beach users, and particularly local participants, are overconfident in their ability to identify rip channels and currents. The focus of beach users on heavy surf as an indication of the rip current potential and the overconfidence in identifying a rip channel or current affects the spatial distribution of beach users and to some degree the location of rescues and drownings. While it can be quite difficult for the average beach user to identify rip channels and active rip currents, the results of the study suggest a need for further education efforts to reduce the rip hazard, particularly in areas where lifeguards are not permanently stationed. 相似文献
4.
Thomas W. Schmidlin 《Natural Hazards》2009,50(1):13-25
There were 407 deaths from wind-related tree failures in the United States, 1995–2007. The most common cause of the deadly
fallen tree was a thunderstorm (41%), followed by nonconvective high winds (35%), tropical cyclones (14%), tornadoes (7%),
and snow and ice (3%). Most (62%) of the deaths were males while the median age was 44 years. The most common location of
the fatality was in a vehicle struck by the tree or a vehicle that crashed into a downed tree on the road (44%), followed
by persons outdoors (38%), in mobile homes (9%), and in frame houses (9%). Persons killed by wind-related tree failures during
tropical cyclones and tornadoes were more commonly at home (40%) when struck than those killed at home by thunderstorm and
nonconvective high winds (13%). Seasonality of the deaths varied by weather type with deaths in thunderstorms clustered during
May–August, nonconvective high winds October–April, tropical cyclones August–October, tornadoes in April and November, and
snow and ice December–April. Regional patterns result from frequency of the wind events, population density, and tree cover.
Suggestions are made for hazard reductions. 相似文献
5.
Reported avalanche fatalities in the United States increased markedly through the latter half of the twentieth century, a
result of the increasing popularity of winter sports. Despite this increase, the literature concerning US avalanche fatalities
is sparse. This paper presents a comparison of three US databases containing avalanche fatality information: Storm Data, the West Wide Avalanche Network (WWAN) dataset, and the National Avalanche Database (NAD). The frequency of avalanche fatalities,
their temporal trends, spatial distributions, and the demographic characteristics of the victims were analyzed in each database
for the years 1998–2009 for the US mountainous west. The data were then pooled to arrive at an estimate of avalanche fatality
frequency in the United States for the study period. While the results indicate a considerable amount of overlap between the
datasets, Storm Data reports fewer avalanche fatalities than both the WWAN and NAD datasets. All three datasets report a maximum of fatalities
in January and display three spatial maxima: the Rocky Mountains of west-central Colorado, the intermountain region from central
Utah through Idaho to west-central Montana, and the northern Cascade Ranges of Washington; however, a large void appears in
the Storm Data records in the vicinity of the Montana maximum. These maxima result from a juxtaposition of avalanche hazard in these mountainous
environments with a high concentration of winter sports activities. 相似文献
6.
Motor vehicles historically have been dangerous locations to shelter in during tornado events. Throughout the twentieth century, motor vehicle design has become safer while tornado forecasting has become better understood. Despite such advances, tornado fatalities in motor vehicles still occur today, and some events periodically result in high numbers of deaths (e.g., ten motor vehicle occupants were killed by a single tornado in Garland, Texas, in 2015). We seek to examine all US tornado-induced motor vehicle fatalities documented between 1991 and 2015. Our findings indicate that motor vehicle fatalities have not significantly changed during this study period. We attribute annual fatality totals to persons lacking awareness of impending dangers coupled with numbers of significant tornado events for a given year. We find most fatalities result when vehicles are lofted or passengers are ejected, and this most typically occurs at the EF3–EF5 intensity thresholds. Fatalities that occur at weaker tornado winds (EF0–EF2) are most often attributed to collapsing debris (mostly trees) on vehicles. Spatially, motor vehicle fatalities are greatest in the Deep South and southern Great Plains regions where overall tornado and nighttime tornado frequencies are greatest. Some of the largest motor vehicle fatality events have resulted from tornadoes not being distinctly visible to motorists; such events have been characterized by tornadoes occurring at night or by tornadoes not appearing as “classic funnels.” 相似文献
7.
Debris flows and their toll on human life: a global analysis of debris-flow fatalities from 1950 to 2011 总被引：1，自引：0，他引：1
Debris flows cause significant damage and fatalities throughout the world. This study addresses the overall impacts of debris flows on a global scale from 1950 to 2011. Two hundred and thirteen events with 77,779 fatalities have been recorded from academic publications, newspapers, and personal correspondence. Spatial, temporal, and physical characteristics have been documented and evaluated. In addition, multiple socioeconomic indicators have been reviewed and statistically analyzed to evaluate whether vulnerable populations are disproportionately affected by debris flows. This research provides evidence that higher levels of fatalities tend to occur in developing countries, characterized by significant poverty, more corrupt governments, and weaker healthcare systems. The median number of fatalities per recorded deadly debris flow in developing countries is 23, while in advanced countries, this value is only 6 fatalities per flow. The analysis also indicates that the most common trigger for fatal events is extreme precipitation, particularly in the form of large seasonal storms such as cyclones and monsoon storms. Rainfall caused or triggered 143 of the 213 fatal debris flows within the database. However, it is the more uncommon and catastrophic triggers, such as earthquakes and landslide dam bursts, that tend to create debris flows with the highest number of fatalities. These events have a median fatality count >500, while rainfall-induced debris flows have a median fatality rate of only 9 per event. 相似文献
8.
Tornado fatalities and mobile homes in the United States 总被引：1，自引：1，他引：0
Fatalities from tornadoes have declined dramatically over the last century in the United States. Despite the overall reduction
in tornado lethality, fatalities from mobile homes remain high. In fact, research suggests that the likelihood of a fatality
in a mobile home is ten times or more than that in a permanent home. This study examines possible explanations of the mobile
home tornado problem, including the potential for concentration of these homes in tornado prone states, the relation to Fujita
Scale rating, and incidence during the day. We find that mobile home fatalities are concentrated in the Southeastern US, significantly
more likely in weaker tornadoes, and occur disproportionately at night. 相似文献
9.
Richard G. Vos 《Sedimentary Geology》1976,16(1):15-19
A model for the formation and location of transient rip currents is proposed. It is suggested that sucking and erosive effects at the peak site (highest part) of a set of large breaking waves initiate a seaward current in a scoured breaker zone, at the same time that water is accumulating inside the breakers. Accumulated water inside the breakers immediately begins to drain seaward through the peak site, feeding this embryonic rip current, which develops into a mature rip current. Rip-current formation in this manner best occurs following storms when a moderate swell, negligible or offshore winds and a flat shoreface profile are present. 相似文献
10.
为研究叠加波浪场的裂流特征,在平直沙坝海岸地形进行了叠加波浪形成的沿岸波高周期性变化的裂流试验研究。试验中叠加波浪是由波浪在垂直岸线的丁坝反射所形成的两列交叉波浪叠加产生,交叉波浪是具有等频率但入射角相反的两波列。通过对叠加波浪节腹点垂直岸线位置浪高的测量和沙坝范围内沿岸布置的声学多普勒测速仪流速测量结果来分析沙坝海岸丁坝反射波形成的裂流特性,讨论了波浪节腹点对裂流位置和裂流空间尺度的影响。对不同周期情况在x=5 m沙坝顶处的速度剖面对比,分析了不同周期对裂流的影响。 相似文献
11.
Perception of the rip current hazard on Galveston Island and North Padre Island,Texas, USA 总被引：1，自引：1，他引：0
Christian Brannstrom Sarah Trimble Anna Santos Heather Lee Brown Chris Houser 《Natural Hazards》2014,72(2):1123-1138
The hazard posed by a rip current depends in part on the ability of beach users to identify a rip current and to associate surf conditions with the potential for rip currents. Understanding which visual features beach users associated with rip currents is an important step in the development of appropriate programs and educational materials aimed at improving the ability of beach users to identify a rip current. A face-to-face survey (n = 392) was conducted to assess the ability of beach users to identify a rip current using five near eye-level photographs that simulate the view of the beach and surf zone as the respondent approached the beach. The survey was conducted on three heavily used public beaches in Texas (Galveston, Port Aransas, and Corpus Christi) at the height of the summer beach season in 2012. Only 13 % of respondents correctly selected the photograph showing the most hazardous conditions and correctly identified the precise location of the rip current on the photograph. The majority of beach users (87 %) incorrectly indicated that the photograph with the heaviest surf represented the most hazardous surf conditions and greatest potential for the development of rip currents, or failed to identify rip currents in photographs. Respondents who were able to correctly identify the rip current tended to recognize the breaking wave pattern, areas of darker water, or the proximity to structures as key visual characteristics of rip currents and also had higher self-reported abilities to swim in rough water and escape a rip current. 相似文献
12.
Fatal landslides in Europe 总被引：4，自引：3，他引：1
Ubydul Haque Philipp Blum Paula F. da Silva Peter Andersen Jürgen Pilz Sergey R. Chalov Jean-Philippe Malet Mateja Jemec Auflič Norina Andres Eleftheria Poyiadji Pedro C. Lamas Wenyi Zhang Igor Peshevski Halldór G. Pétursson Tayfun Kurt Nikolai Dobrev Juan Carlos García-Davalillo Matina Halkia Stefano Ferri George Gaprindashvili Johanna Engström David Keellings 《Landslides》2016,13(6):1545-1554
Landslides are a major hazard causing human and large economic losses worldwide. However, the quantification of fatalities and casualties is highly underestimated and incomplete, thus, the estimation of landslide risk is rather ambitious. Hence, a spatio-temporal distribution of deadly landslides is presented for 27 European countries over the last 20 years (1995–2014). Catastrophic landslides are widely distributed throughout Europe, however, with a great concentration in mountainous areas. In the studied period, a total of 1370 deaths and 784 injuries were reported resulting from 476 landslides. Turkey showed the highest fatalities with 335. An increasing trend of fatal landslides is observed, with a pronounced number of fatalities in the latest period from 2008 to 2014. The latter are mostly triggered by natural extreme events such as storms (i.e., heavy rainfall), earthquakes, and floods and only minor by human activities, such as mining and excavation works. Average economic loss per year in Europe is approximately 4.7 billion Euros. This study serves as baseline information for further risk mapping by integrating deadly landslide locations, local land use data, and will therefore help countries to protect human lives and property. 相似文献
13.
Natural hazards are natural processes of the complex Earth system and may interact and affect each other. Often a single hazard can trigger a subsequent, different hazard, such as earthquakes triggering landslides. The effect of such cascading hazards has received relatively little attention in the literature. The majority of previous research has focused on single hazards in isolation, and even multi-hazard risk assessment currently does not account for the interaction between hazards, therefore ignoring potential amplification effects. Global earthquake-and-landslide fatality data were used to model cascading events to explore relationships between the number of fatalities during single and cascading events and covariates. A multivariate statistical approach was used to model the relationship between earthquake fatalities and several covariates. The covariates included earthquake magnitude, gross domestic product, slope, poverty, health, access to cities, exposed population to earthquake shaking, building strength and whether a landslide was triggered or not. Multivariate regression analysis showed the numbers of earthquake fatalities are significantly affected by whether a subsequent landslide is triggered or not. 相似文献
14.
Evaluation of swimmer-based rip current escape strategies 总被引：2，自引：1，他引：1
R. Jak McCarroll Robert W. Brander Jamie H. MacMahan Ian L. Turner Ad J. H. M. Reniers Jenna A. Brown Anthony Bradstreet Shauna Sherker 《Natural Hazards》2014,71(3):1821-1846
Rip currents are the primary hazard on surf beaches, and early studies described them as fast, shore-normal flows that extended seaward of the surf zone. Based on this traditional view, commonly promoted safety advice was to escape a rip current by swimming parallel to the beach. However, recent studies have shown dominant rip current re-circulation within the surf zone and have endorsed floating as an appropriate escape strategy. Here, a first quantitative assessment of the efficacy of various rip current escape strategies, with a focus on the underlying physical processes, is presented. A field study was conducted at Shelly Beach, NSW, Australia, measuring three rip currents (two open beaches, one topographic) over 3 days in varying wave conditions. Floating was found to be a longer duration, more variable escape strategy ( $ \overline{t} $ = 3.8 min, σ = 2.4 min), than swimming parallel ( $ \overline{t} $ = 2.2 min, σ = 1.0 min). Neither of the scenarios is 100 % foolproof, and both fail in some scenarios, making simplified safety recommendations difficult. Swim parallel failures are related to swimming against the alongshore current of the rip circulation. Float failures related to surf zone exits, with the highest exit rate occurring in the topographic rip. Float failures also occurred due to multiple re-circulations without the person attaining safe footing on the bar. The variable spatial and temporal behaviour of rip currents suggests that a single escape strategy safety message is inappropriate. Instead, a combined approach and scenario-specific safety advice should be considered by beach safety practitioners to promote to the public. 相似文献
15.
Many drowning and near drownings at Pensacola Beach, Florida are attributed to rip currents, the strong seaward-flowing currents that extend from the shoreline to the line of breakers and sometimes beyond. While surf forecasts assume that the rip hazard is uniform alongshore and that the (erosion) rips are ephemeral features, evidence is presented to suggest that the rip hazard at Pensacola Beach is not uniform alongshore. Rather the rip current “hotspots” develop as a consequence of an alongshore variation in the surf similarity parameter and nearshore state on the order of ~1,450 m. The variation is forced by transverse ridges on the inner shelf that force wave refraction and focusing at the ridge crests. This creates a more dissipative, rhythmic bar and beach morphology at the ridges and rougher surf. Between ridges, where wave heights and periods are smaller and the outermost bar is forced closer to the shoreline, the nearshore is in a (more reflective) bar and rip state during red flag conditions. Drownings between 2000 and 2009 are shown to be clustered between transverse ridges and in the years following a hurricane or tropical storm (2000–2003 and 2005–2008) when the bar and rip morphology first develops as the shore face recovers. This continues until the innermost bar attaches to the beach face unless the bar system is reset by another tropical storm or hurricane. It is argued that the rip hazard is dependent on the alongshore covariation of the environmental forcing with the individual and group behavior in both time and space, even on what appears to be a relatively uniform beach environment. 相似文献
16.
James H. Power 《Estuaries and Coasts》1997,20(2):312-318
Many species appear to selectively use tidal currents for transport into or out of estuaries, or to maintain residence within an estuary. Further, some species are preferentially active during nocturnal hours, possibly to reduce their vulnerability to predators. The interaction between predicted tidal current flow and the day-night cycle was investigated for 11 locations within the United States. Tidal current constants for each of these were obtained from the United States National Ocean Survey. Additionally, times of sunrise and sunset were computed for each location and day between the years 1978 and 2000. These sets of information were combined by integrating the predicted current velocity between successive times of sunrise or sunset or times of slack current for each day and location. The result is the average daily net transport possible at that time and location. Plots of these transport values reveal seasonal patterns when either transport in a preferred direction or retention is more readily accomplished. Such calculations do not incorporate other influences on tidal currents, such as variations in winds or freshwater discharge, but they do reveal the consistent seasonal and regional opportunities for transport or retention that a species would encounter over long time spans. 相似文献
17.
Tropical cyclone (TC) disasters have frequently caused casualties in the coastal areas of China. According to the statistics of dead and missing people due to TCs from 1951 to 2014, the number of fatalities has been significantly decreasing over time. However, deadly TC events have still caused great losses of life in recent years, which are characterized as significant abrupt fluctuations superimposed along the downward trend of the long-term fatality time series. The numbers of fatalities caused by TC disasters are influenced by variables such as the intensity of TC hazards, the population exposed to TCs and the vulnerability of people to TC hazards. It is thus of great significance to analyze their temporal characteristics and understand the forces driving these changes. First, the time series of the TC wind, precipitation, spatial distribution of population, fatality and disaster risk reduction (DRR) measures of China from 1951 to 2014 are reconstructed. Second, the improved power dissipation index, total precipitation, integrated intensity and index of exposed population are calculated, and the population vulnerability indices, including mean and relative fatality rates, are derived. Third, the change trend of each index is detected using the Mann–Kendall test. Finally, the main driving factors of the long-term change trend and fluctuations of the TC fatalities are analyzed by a negative binomial regression model and standard deviation statistics. It is found that the decrease in vulnerability based on the improvement in structural and non-structural measures is the main driving force of the decreases in fatalities over the past six decades. Although the total population and exposure have increased dramatically in the coastal areas of China, their contributions to the increase in the fatality risk were counteracted by the decrease in vulnerability. Abrupt and catastrophic disasters were mostly caused by TCs with hazards of high intensity that surpassed the capacity of structural measures; the lack of forecasting or early warning, as well as improper emergency response actions, may also have triggered the great loss of lives. To reduce the fatalities of future TCs, especially those that may exceed the capacity of structural measures, the enhancement of non-structural measures and the adaptation of resilience strategies should be priorities for future people-centered disaster management.
相似文献18.
Drowning accidents at beach in Japan are caused by rip currents. To reduce these accidents, a new technology that can detect rip currents and notify beachgoers by using the Internet of Things (IoT) and Artificial Intelligence (AI) was proposed. However, studies on the effect of visualizing rip currents or considering the effect of optimism bias have not been conducted. This study investigates if visualization of rip currents might help in preventing drowning accidents, while considering the effect of optimism bias. The participants were 90 Japanese beachgoers. They were asked to answer questions based on their knowledge of the beach and rip currents, their optimism bias regarding rip currents, and awareness with or without visualization. The results of the analyses suggest that despite optimism bias, the visualization of rip currents increases the tendency of beachgoers to perceive and avoid rip currents. As described above, it was found that by visualizing the rip current, beachgoers were able to perceive and avoid rip currents. In addition, an understanding of rip currents is positively related to the intent to avoid rip currents even when rip currents are visualized. Therefore, it is necessary not only to enhance the avoidance tendency by visualizing rip currents, but also to further enhance knowledge of beachgoers to deepen the understanding of rip currents including the danger associated and methods to avoid them.
相似文献19.
Rip currents represent significant hazards to swimmers all around the world. The danger arises when a misinformed swimmer uses an inadequate strategy to escape the rip, such as fighting the current directly. This can lead to fatigue, panic, and in some cases drowning. There exists a range of strategies put forward by experts (both lifeguards and scientists) to escape rip currents. However, these recommendations are based on a limited number of scientific studies and there is still much discrepancy surrounding the best strategy to escape a rip. Thus, here we present a simple, physics-based theoretical model aimed at assessing different escape strategies in terms of their associated ‘energetic cost’ (in work and power) for any given rip current and swimmer’s proficiency level. Many combinations of swimmers and rips are considered, including both idealised and a realistic rip current. Our quantitative results back the common knowledge that swimming against the rip (which is strongly discouraged by lifeguards) is almost universally the worst possible strategy, especially when compared against strategies favoured by experts, such as floating with the current before attempting to swim back to the shore. For a realistic rip, our results suggest that swimming directly against the rip can require several times more power from the swimmer than other strategies advised by lifeguards, thus lending further scientific support to experts’ recommendations. This study may help promote education around the dangers posed by rip currents and how best to address them.
相似文献20.
The delivery, flux and fate of terrigenous sediment entering the Great Barrier Reef lagoon has been a focus of recent studies and represents an ongoing environmental concern. Wave‐induced bed stress is the most significant mechanism of sediment resuspension in the Great Barrier Reef, and field data and mathematical modelling indicates that the combined effects of short‐period wind waves, longer period swell waves, and tidal and wind‐driven currents can often exceed the critical bed stress for resuspension. Suspended‐sediment concentrations at 20 m water depth indicate resuspension seldom occurs on the middle shelf under normal wave conditions. Non‐cyclonic turbidity events are generally confined to the inner shelf. The wave climate in the southern sector of the central Great Barrier Reef lagoon is the most erosive, and resuspension of outer shelf sediments was hindcast for recorded cyclones. Wind‐driven, longshore currents are fundamental to the northward movement of sediment, and the annual northward mass flux from embayments undergoing resuspension in the Burdekin region is estimated to be one order of magnitude larger than the mass of sediment introduced by a moderate flood plume. Strong onshore winds are estimated to generate significant three‐dimensional bottom return currents on approximately 30–70 days per year, forming a potentially significant offshore‐directed sediment flux during high suspended‐sediment concentration events on the inner shelf. 相似文献