Easily read eBooks on smart phones, computers, or any eBook readers, including Kindle. We cannot process tax exempt orders online. If you wish to place a tax exempt order please contact us. Add to cart. Sales tax will be calculated at check-out. Physical location dictates exactly what profile of natural hazards a nation must face.
Economic, industrial, and sociopolitical factors dictate hazards of technological and intentional origin. And with globalization, the speed and ease of international travel, and the emergence of global climate change patterns, it is apparent that every nation may be considered a neighbor of every other nation on the planet. This chapter will begin with a short description of the disaster management processes of hazard identification and hazard analysis sometimes referred to as hazard profiling.
This will be followed by a listing and description of many of the hazards that possess catastrophic potential—in other words, those hazards that are capable of causing a disaster. The first step that must be taken in any effective disaster management effort is the identification and profiling of hazards. The actual number of possible hazards throughout the world is staggering, and the list is by no means limited to what is found in this, or any other, text.
However, disaster managers must be able to identify those hazards that are most likely to occur and that are most devastating should they occur. Understandably, it is impossible to plan for or prevent every possible contingency, so most government and other organized emergency management entities will focus their efforts upon those hazards that would be likely to result in the greatest undesirable consequences.
Disaster managers must attempt to identify every scenario that could possibly occur within a given community or country as result of its geologic, meteorological, hydrologic, biological, economic, technological, political, and social factors. This 31 32 hazard assessment, as it is often called, must include not only the actual physical hazards that exist but also the expected secondary hazards, including social reactions and conditions.
In order to begin the processes of risk analysis and risk assessment, which are covered in subsequent chapters, community leaders must identify all of the hazards that the community has experienced in the past and could possibly experience in the future.
It is also important, at least in the initial stages of the process, to identify all other possible hazards, regardless of how small their likelihood of occurrence. As will be discussed in Chapter 3, many hazards are extremely unlikely to occur but, due to the nature of their consequences, their mitigation measures must be considered. The goal of hazard identification is to establish an exhaustive list of hazards upon which further analysis can be performed. Again, it is not the concern of those identifying the hazards to consider what their likelihood or consequences may be.
This is a process in which more is definitely better. A hazard, as defined in Chapter 1, is a source of potential harm to a community, including its population, environment, private and public property, infrastructure, and businesses. For ease of description, hazards can be categorized into several subgroups, namely natural hazards, technological hazards, and intentional hazards.
These categories are but one of many ways in which hazards can be subdivided. Other classification systems may involve more or fewer categories and may use different terminology. What is important, however, is that the categories chosen accommodate the full range of hazards such that no group is overlooked. It is not uncommon for hazards from one of the chosen categories to cause a secondary hazard or disaster in that same category or one of the others.
Hazard sequencing, described below, helps to determine these secondary, tertiary, or further disasters. Additionally, some hazards may be correctly placed in more than one category, which can lead to confusion. The division of hazards into these respective lists, however, helps to provide direction to governments or Introduction to International Disaster Management groups tasked with hazard identification, and adds logic to the thought process by which the hazards are identified.
For most countries, natural hazards are the primary concern of disaster managers. These hazards, which can occur after the failure of existing technology, tend to be much less understood than their natural counterparts and are increasing in number as the scope of and dependence on technology expands.
Intentional hazards is the third category, and includes those hazards that result from the conscious decision of man to act in an antisocial or antiestablishment manner. Like technological hazards, many of these hazards are new and emerging, such as modern biological, chemical, and radiological weapons.
Others, such as war, have existed for almost as long as humans themselves. Hazard identification must be exhaustive to be effective. The product of this process, which is a detailed list of all past disasters and all possible future hazards within the country or community, will be the basis upon which effective disaster management policies and projects may be based.
The breadth of knowledge and experience of the team assembled to complete such a process will ultimately be a determinate factor guiding how complete and accurate the generated hazard list will be. Also, because of risk perception explained in Chapter 3 , which defines how different people perceive hazard significance, a wide range of viewpoints is highly beneficial.
When identifying hazards, it is important to remember that the process is used simply to identify all of the hazards that might affect the country. It is not Chapter 2 Hazards concerned with the severity of their impact or the likelihood of occurrence.
Ideally, all hazards with likelihood greater than zero would be identified and their associated risks reduced. However, determining which hazards are treated comes later, and only after hazards are compared as will be explained in Chapter 3 can hazard priorities be ranked. Additionally, it is often difficult to understand whether even a seemingly insignificant hazard could trigger a much larger secondary hazard.
There are several methods by which hazard identification can be conducted. Ideally, a number of these will be used in conjunction. Some methods can be performed simultaneously, while others follow a logical step-by-step approach.
Hazard identification is often used to initiate hazard profiling, which is a process of describing the hazard in its local context. This includes a general description of the hazard, its local historical background, local vulnerability, possible consequences, and estimated likelihood.
Checklists, which are comprehensive lists of hazards, consequences, or vulnerabilities, provide reference information to those performing risk analysis. It is often recommended that the use of checklists be limited until the process has reached an advanced stage. If they must be used to start the hazard identification process, their importance should be downplayed.
Therefore, checklists should be brought in at a later time to ensure that nothing has been left out of consideration or overlooked. Hazard identification methods can be grouped into two categories: prescriptive and creative. Whichever method is chosen, it is important that a cost- and timeeffective overall methodology is established that caters specifically to the needs and capabilities of the 33 government agency or organization performing the hazard risk assessment.
This methodology should incorporate several of the methods listed below, either in part or completely. Because this process could be performed indefinitely, the disaster management team must establish a goal that defines when the process has reached a satisfactory end point. This creative process, in which disaster managers use their own knowledge and experience to develop a list of possible hazards, is one of the most effective methods of hazard identification.
There are several ways in which the process can be conducted, including workshops, structured interviews, and questionnaires. Whatever methods are used, the quality of the end product will correlate directly with the background, diversity, and experience of the individuals involved in the exercise.
Presumably, incident reports on past events exist and will generate a list of known hazards. Many of these resources will provide dates, magnitudes, damages, and further evidence of past disasters in the community or state.
Reviews of existing plans. Various types of plans exist within the government local to national that may contain information on hazards. National or local transportation, environmental, dam, or public works reports or plans are often useful. Others sources include local police, fire, or emergency management action plans, land use plans, capital improvement plans, building codes, land development regulations, and flood ordinances.
Investigation of similar hazard identification efforts in neighboring countries. Many disasters will extend beyond country borders. Investigations of neighboring countries also may turn up natural or technological hazards not present in the original country but that could result in a regional disaster within the country of focus as with the Chernobyl disaster, in which fallout was carried by wind and weather to many adjacent countries.
Use of maps. Disaster managers can use maps to overlay known settlement, topographic, hydrologic, and other environmental and technological characteristics in order to determine whether interactions between these factors could result in unforeseen hazards. Interviews with local citizens, risk managers, community leaders, academics, nonprofit relief agencies, international organizations, and other municipal and private sector staff many of which are described in later chapters who regularly perform disaster management tasks can provide a wealth of information.
Floodplain managers, public works departments, and engineering, planning and zoning, and transportation departments commonly keep records on past and possible future hazards. Fire departments, police departments, and emergency management offices are bound to have a wealth of insight and information.
Site visits to public or private facilities. Public or private facilities that serve as a known source of risk for the community are likely to provide information not only on the hazards they create but also about external factors identified by their own risk management departments as a source of risk for the facility. Determining the secondary hazards that can arise from the hazards already identified is commonly done using simple brainstorming, or hazard sequencing. Hazard sequencing is most often performed using event trees or fault trees.
There are two primary methods of creating event trees. The first method, shown in Figure , begins by focusing on the effects of a single identified hazard and then focuses on the subsequent effects of those effects, and so on. The process is repeated until the disaster managers feel all possible secondary effects have been listed. The second method is very similar to the first, except that it examines all of the events that may occur over the course of a hazard scenario.
Figure depicts the analysis of one of many possible initiating events. For more information on event trees, see Kaplan, Fault trees differ from event trees in that they focus on the end state, or consequence, and trace back to the possible initiating events hazards that could have triggered the consequence.
The first of two methods, shown in Figure , begins by focusing on the possible causes of a single identified consequence and then focuses on the subsequent causes of those causes, and so on.
The process is repeated until all possible causes of the consequence have been listed. The second method, depicted in Figure , is similar, except that all of the causes, or initiating events, of a consequence are mapped according to a timelinebased scenario. This fault tree method begins by identifying the consequence, and then examining the scenario for any possible triggering events that could eventually lead to that end state. Once a hazard has been identified, it must be further described for later use in risk analysis.
This descriptive process, called hazard analysis or hazard profiling, allows disaster managers to make more informed calculations of risk, upon which disaster management actions are ultimately taken. Each hazard will be different in this respect, due to climate, geography, settlement patterns, regional and local political and stability, among many other factors.
Disaster managers commonly create what is called a risk statement, which serves to summarize all of the necessary information into a succinct report for each identified hazard. With these reports, disaster managers can more accurately address each hazard in the specific context of the community or country.
In disaster management, a risk statement tells the disaster manager how each hazard impacts that community. Adapted from Kaplan, Fault tree. Adapted from Slovic, Fischhoff, and Lichtenstein, Even people with extensive backgrounds in hazards may have little or no understanding of how those hazards affect a community or country. This knowledge requires information about a combination of general hazard information and descriptions, community and environmental factors, and vulnerability factors described in Chapter 3.
There are several methods of generating risk statements, and the main elements of this process are described below. If done incorrectly, however, they can cause unnecessary confusion and be counterproductive to the disaster management process as a whole. To begin profiling hazards, it is vital that a base map be obtained or created. A base map contains important geographical, political, population, and other information upon which hazard information may be overlaid. It is essentially a geographic representation of the community or country as a whole, sometimes called a community profile.
Includes topography, mountains, bodies of moving and standing water, canyons, coastal zones, tectonic faults, and other features Property. Includes land use, construction type, essential facilities, and hazardous materials facilities, among others Infrastructure. Includes roads, rail lines, airports, utilities, pipelines, bridges, communications, and mass transit systems, among others Demographics.
Includes the locations, facilities, services, and assets of fire, police, emergency management, military, public health, and other response systems Each hazard that threatens a community will affect it in a unique way.
For instance, while heavy rain may be expected to uniformly affect a whole community, landslides and mudflows will only be a problem where there are steep, unstable slopes.
The base map is the best way for disaster managers to analyze the spatial extent of hazards and thus plan for the possibility of interaction between hazards and people, structures, infrastructure, the environment, and so on. To truly compare and analyze risks, it is important that risks are represented individually on a base map, as well as together on a single aggregate risk map.
If a standardized map is used for all hazards profiled, disaster managers can maximize the possibility that all the mapped hazards account for timeliness and that there are no errors made due to scale of size, and they can simplify the task of comparing or combining two or more risk maps.
Once hazard maps are generated, disaster managers may move on to creating risk statements. Risk statements, like risk maps, are most effective if data is collected using a standardized format of information retrieval and reporting. A standardized display format ensures that detailed information is both easily readable and understandable to those involved in future steps of the disaster management process.
The contents of the risk statements should include but are not limited to, and not necessarily in the order presented : 1. Name of the hazard. Many hazards have different names, so it is important that a risk statement clearly identify exactly what type of hazard is being profiled.
Providing a descriptive hazard identifier minimizes confusion. General description of the hazard. The range of individuals involved in the exhaustive disaster management process probably will have many different levels of knowledge and understanding about the hazards to be analyzed.
Additionally, many measurement and rating mechanisms for hazards have changed over time, and others may be extremely useful in determining the local context of a hazard. Frequency of occurrence of the hazard. This includes: a. Historical incidences of the hazard.
This could be displayed in a standardized format, either as a spreadsheet, chart, or list. If the hazard happens regularly, it may be indicated as such, with only major events listed. This is often true with floods and snowstorms, for example. Predicted frequency of the hazard. Actual frequencies will be expanded upon in the risk analysis step detailed in Chapter 3. Magnitude and potential intensity of the hazard. Based upon the hazard maps, this measure may be a single figure or a range of possibilities.
The magnitude and possible intensity will be important during risk analysis, as these figures help disaster managers to determine the possible consequences of each hazard and to determine what mitigation measures are appropriate.
Location s of the hazard. For most hazards, the basic hazard map will be both sufficient and highly informative during risk analysis. However, when there are individual areas or regions within the community or country that require special mention and, likewise, special consideration, this may be included as a separate comment or detail. This helps to ensure that those special areas are not overlooked in subsequent processes.
Estimated spatial extent of impact of the hazard. This information is also likely to be found on hazard maps. However, there may be special additional comments or facts for some hazards that need to be included sepa- Chapter 2 f. Hazards rately from the visual representation provided by the map. Duration of hazard event, emergency, or disaster. However, for disasters that rarely occur or have never occurred, such as a nuclear accident or a specific type of hazardous material spill, estimations are often provided, based upon the hazard description, community vulnerability see Chapter 3 , emergency response capability Chapter 6 , and anticipated international response assistance.
This figure will generally be a rough estimate, measured in days rather than hours or minutes, but will be very useful in subsequent steps that analyze possible consequences. Seasonal pattern or other time-based patterns of the hazard. This is simply a description of the time of year that a hazard is most likely to appear, if such a pattern exists. Knowing seasonal patterns allows disaster managers to analyze interactions between hazards that could occur simultaneously.
Speed of onset of the hazard event. The speed of onset of a hazard can help planners in the mitigation phase determine what actions are possible, impossible, and vital given the amount of predisaster time they are likely to have. The public education and communications systems that are planned will be drastically different for each action. Warning systems and evacuation plans must reflect the availability or lack of time within which action can be taken.
If responders can be readied before the disaster, the speed of response will be increased significantly. For these reasons and many more, knowing the speed of onset of a hazard is vital in planning. Availability of warnings for the hazard. This information is indirectly related to the speed 39 of onset of a hazard, but is also independent in some ways. Each hazard is distinct and has certain characteristics that either do or do not lend themselves to prediction. Some hazards that have a fast onset, such as a volcanic eruption, can be predicted with some degree of confidence though not always , while some hazards with slower onset times, such as biological terrorism, can not be predicted accurately at all.
Yet other hazards provide no advance warning at all, such as a chemical accident. Even if advance knowledge of a disaster is possible, the capabilities of the local warning system further determine the possibility of adequately informing the public about an impending disaster.
All factors must be considered when determining warning availability. Once the obtainable information listed above has been collected, it should be presented in a standardized, easy-to-read display format.
However, the many forces that elicit these disasters are in fact natural phenomena that occur regardless of the presence of man.
Source: USGS, a. The following section identifies the most common of these natural processes and briefly describes each. Plate tectonics is a study of the movement of these plates, and combines the theories of continental drift and sea-floor spreading.
Where the plates interact along their margins, many important geological processes occur: mountain chains are formed and lifted, earthquakes begin, and volcanoes emerge. We now know that there are seven major crustal plates, shown in Figure , which are subdivided into a number of smaller plates.
They are about 80 kilometers thick and are all in constant motion relative to one another, at rates varying from 10 to millimeters per year. Their pattern is neither symmetrical nor simple. The specific type of interaction between plates, including collision, subduction one plate sliding under another , or separation, determines the kind of tectonic hazard.
These hazards occur most often at the boundaries of the great plates, where the interactions originate, but they are by no means limited to these convergent zones. Earthquakes, which as their name suggests are sudden movements of Earth, are caused by an abrupt release of strains that have accumulated over time along fault lines.
The rigid, constantly moving plates often become stuck together at points along their boundaries, and are unable to release the energy that slowly accumulates. Eventually, this snag is released, and the plates snap apart. Source: www. Seismic waves are generated by the jolting motion of the plates, and extend outward from the origination point, or epicenter, like ripples formed by a stone thrown into a pond.
The speed of those waves depends upon the geologic makeup of the materials through which they are passing. For particularly large earthquakes, such as the event that caused the tsunami events in Asia, the entire world can vibrate for several seconds or minutes. Strike-slip lateral faults occur in response to either type of stress; the blocks move horizontally past one another. Most faulting along spreading zones is normal, along subduction zones is thrust, and along transform faults is strike-slip in spreading zones, plates move away from each other; in subduction zones plates move towards each other, with one sliding beneath the other; transform faults occur when plates slide laterally against each other, in opposite directions.
Earthquakes can occur at a range of depths. Focal depths from 0 to 70 kilometers The focal point may be as deep as kilometers miles. Although earthquakes can be generated by volcanic activity see below or by manmade explosions, the most destructive events are those resulting from plate slippage. Earthquakes are generally measured according to their magnitude and intensity. The commonly referred-to Richter Scale, named after its creator Charles Richter, is an open-ended logarithmic scale that measures the magnitude, or amount of energy released, by the earthquake, as detected by a seismograph.
Most events below 3 are imperceptible to humans, while those above 6 tend to cause damage. Very few earthquakes exceed 9 on the Richter scale. Table illustrates the average number of quakes that occur per year within each point on the Richter scale. The MMI is useful in determining how a single earthquake affects different geographical areas because, unlike the Richter scale where the event has a single magnitude, different intensities can be assigned to any variant of geographic determination.
Based on observations since Exhibit describes the observations associated with each level of intensity on the MMI scale. When loosely packed, waterlogged sediments are exposed to a certain degree of seismic strength depending on the exact soil makeup , that land becomes jelly-like and loses its ability to support structures. Buildings can lean, topple, or collapse quite easily under these conditions.
Many secondary hazards and, likewise, disasters are known to occur in the aftermath of an earthquake. The shaking can cause unstable slopes to give way, resulting in landslides that can be more devastating than the quake itself. The El Salvador earthquakes, in which the vast majority of the victims died from a series of resulting slides, is but one example.
Rockslides and avalanches, both described later in this chapter, are common secondary hazards to earthquakes. Not felt except by a very few under especially favorable conditions. Felt only by a few persons at rest, especially on upper floors of buildings.
Felt quite noticeably by persons indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated. Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building.
Standing motor cars rocked noticeably. Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight. A single, high-magnitude earthquake off the coast of Indonesia caused the tsunami events throughout Asia. Tsunamis are described in greater detail below. At certain points along the VIII. Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse.
Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, and walls. Heavy furniture overturned. Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse.
Buildings shifted off foundations. Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent. Few, if any masonry structures remain standing. Bridges destroyed. Rails bent greatly. Damage total. Lines of sight and level are distorted.
Objects thrown into the air. Source: USGS, There are currently over active volcanoes throughout the world see Figure The plate can then melt into magma, creating a buildup of pressurized material that is thrust to the surface, often explosively.
Rift volcanoes occur when two plates move away from each other, allowing magma to rise to the surface through the intervening space. These volcanoes tend to be associated with low magma pressure and therefore are not often explosive. Hotspot volcanoes occur when there is a weak spot within the interior of a plate under which magma can push through to the surface. Many of the Pacific islands, including the Hawaiian island chain see Figure , are hotspot volcanoes Smith, The resulting depression is called a caldera.
These spaces can be more than 25 kilometers in diameter and several kilometers deep. Cinder cones are simple volcanic structures formed by particles and congealed lava ejected from a single vent. Most cinder cones have a bowlshaped crater at the summit and rarely rise more than 1, feet above their surroundings.
Composite volcanoes and stratovolcanoes. These structures typically are very large, steep-sided, symmetrical cones made from alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs blocks are large greater than 64 mm diameter rock fragments that are ejected from the volcano in a solid form; bombs are volcanic material that is ejected in a liquid state, but which cools to a solid form before falling to the ground.
The volcano is built up by the accumulation of material erupted through the conduit and increases in size as lava, cinders, ash, etc. Continental volcanoes. These volcanoes are located in unstable, mountainous belts that have thick roots of granite or granite-like rock. Magma is generated near the base of the mountain root, and rises slowly or intermittently along fractures in the crust.
A chain of islands is often thrust up in an arc shape from the ocean floor. Examples include the Aleutian Islands and Japan. Eruptions associated with these processes tend to be highly explosive.
Lava plateaus. In some shield-volcano eruptions see below , basaltic lava pours out slowly from long fissures instead of central vents and floods the surrounding countryside, forming broad plateaus. Iceland is an example of this kind of volcano. Lava domes. These structures form when lava that is thrust from a vent is too sticky to flow very far and forms a steep mound. Maars tuff cones. These structures are shallow, flat-floored craters that likely have formed above vents as a result of a violent expansion of magmatic gas or steam.
Maars range from to 6, feet across and from 30 to feet deep, and most are filled with water, forming natural lakes. Oceanic volcanoes. These structures are aligned along the crest of a broad ridge that marks an active fracture system in the oceanic crust. Shield volcanoes. These structures are built almost entirely of highly fluid basaltic lava flows. The Hawaiian Islands are shield volcanoes. Submarine volcanoes, ridges, and vents. These undersea structures are common features on certain zones of the ocean floor along plate boundaries.
Some are active and can be seen in shallow water because of steam and rock debris being blasted high above the ocean surface. These volcanoes are formed under a glacier, and are commonly found in Canada.
Each year, approximately 50 volcanoes erupt throughout the world, with fatalities occurring in about 1 out of every 20 eruptions. Volcanoes cause injury, death, and destruction through several means.
Airborne ash and noxious fumes can spread for hundreds of miles, contaminating water supplies, reducing visibility, instigating electrical storms, collapsing roofs, and causing health problems. Lava flows, which can be slow aa lava or fast moving pahoehoe lava , burn everything they contact. Explosions of gas and lava have been known to flatten entire forests.
The great changes that occur within the Earth that are associated with the movement of lava often affect the pressure built up between surface plates, causing minor earthquakes to occur. The explosive nature of the volcano itself can cause the plates to shake as well. Though these events are not often associated with widespread damage, they can cause structural damage to the volcano or surrounding land, leading to rock falls, landslides, or other hazards.
Rockfalls and landslides. As volcanoes erupt, they often shake and become unstable. Sections of the volcano may collapse inward or slough away completely. As this section illustrates, measurement of vulnerability results from a combination of physical, social, economic, and environmental factors or processes. It is important to first clarify the difference between the concepts of vulnerability and exposure, which are often confused. The two words are used interchangeably to describe how a country, region, or community is likely to experience a certain hazard.
However, this is incorrect, as the discussion on vulnerability factors shows. While vulnerability defines the propensity to incur consequences, exposure merely suggests that the individual, structure, community, nation, or other subject will be exposed to the hazard.
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