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2 Classification of Hazards and Risks

Lead-in. Look at the words and phrases in the box, which describe different weather conditions.

1. Which weather conditions are illustrated in the photograph on this page?

2. Group the expressions according to the time of the year these conditions are most likely to occur in your country. Which types of weather rarely or never occur?

Heavy snowfalls

dense fog

strong winds

Thunder and lightning

freezing cold

scorching sun

A heatwave

severe floods

soaring temperatures

Violent storms

high humidity


Torrential rain



Exercise 1. Read the text, do the tasks after it.

Risk is a part of life, but natural disasters boggle the mind. The international impacts of the various types of natural hazards in terms of fatalities are shown in Table 1. Over the interval 1960-87, tropical storms were somewhat more devastating than earthquakes; however, mortality statistics are very closely correlated with specific events, such as the 1970 Bangladesh typhoon, and the earthquake of 1976 near Tangshan, China. Over the course of time, geologic and climatic disasters seem to be about equally deadly.

Table 1

Fatalities from Natural Hazards 1960-1987

Hazard type


Largest event and Date

Death Toll

Tropical cyclones


Eastern Pakistan (Bangladesh) 1970




Tangshan, China 1976




Vietnam 1964


Avalanches, mudslides


Peru 1970


Volcanic eruptions


Columbia 1985




Eastern Pakistan (Bangladesh) 1969


Snow, hail, wind storms


Bangladesh 1986 (hail)


Heat waves


Greece 1987


Note: * Deaths rounded to the nearest hundred

Source: E. Bryant, Natural Hazards, Cambridge University Press, p. 23

Hazards are relatively sudden events (disasters) that endanger lives and property. The ultimate cataclysm for life throughout the solar system would be the explosion of our Sun as a supernova; nearly as devastating would be the terrestrial impact of a large asteroid. Two principle types of hazard may be distinguished: natural and technogenic. Geologic catastrophes such as earthquakes, avalanches, volcanic eruptions, and seismic sea waves (tsunamis), and meteoro- logic-oceanographic disasters such as typhoons, droughts, floods, and lightning- strike forest fires, constitute some of the main types of natural hazard. Technogenic, or human-induced, disasters reflect the unwise, or at least unlucky, impingement of human activities on the environment. Examples of technogenic hazards include the collapse of seawalls, levees, bridges, and buildings; dam failure; chemical and radiation pollution; and war. The anthropogenic-induced gradual degradation of the environment and loss of biodiversity are sure to be calamitous as well, and may have more far-reaching impacts on the planetary web of life. However, natural disasters are defined as characteristically sudden, brief, and in some cases, unexpected events.

Solar radiation impinging on the Earth drives the circulation of the atmosphere and the oceans. The dynamic flow patters we know as weather and ocean currents are manifestations of the redistribution of thermal energy among the fluid envelopes of our planet. Hurricanes, typhoons, and cyclones are simply extreme examples of this energy transfer process. Because the Pacific Ocean is the worlds largest solar energy sink, this basin is the site of the most devastating tropical storms and ocean-induced droughts. Coastal erosion and flooding also constitute a major hazard in low-lying portions of the region. Climatic hazards are well-understood phenomena, however, the underlying reasons accounting for geologic hazards are much less obvious.

Hidden from view, the imperceptible mantle circulation, which is driven by buried heat, produces the crustal motions collectively known as plate tectonics. Such processes are responsible for the differential motions of lithospheric slabs. The boundaries of the plates are marked by intense seismicity, volcanic activity, and land slumpage. Climatic and geologic disasters cause great human suffering and financial loss, especially within the Pacific Basin and around its margins. If global temperatures continue to climb as a consequence of an intensifying greenhouse effect, the ferocity and number of tropical storms will also rise, coastal erosion and flooding will accelerate, and the vulnerability of the worlds burgeoning tidewater communities to devastation by tsunamis will increase. Millions of lives will be endangered, not to mention the economies of the nations affected.

Historically, humans typically have failed to consider natural disasters in the appropriate physical and historic context. Rather, each is viewed as a unique event - typically act of God. Following an earthquake, landslide, flood, typhoon, structures are rebuilt by the survivor and life-style are resumed, in many cases exactly as before the disaster is the same vulnerability with regard to a future event perpetuated. Moreover, as populations grow, their expansion into, and utilization of, hazard-prone, marginal environments increases; consequently, the overall risk is heightened.

Sea-floor spreading, continental drift, and plate tectonics are inexorable manifestations of the transfer of thermal energy from the Earths deep interior toward the surface and the cyclonic storms are a function of solar energy input. These processes will forever lie beyond the limits of human ability to modify them; we can never completely eliminate their accompanying natural catastrophes. Understanding the basic causes of these phenomena means for us to organize our lives and reinforce our structures to minimize the dangers. At all scales information can avert potentially devastating loss of lives through clear recognition and assessment of hazards, appropriate land use, construction of safe ..., and timely, accurate warning of an impending danger, volcanic eruption, landslide, tsunami, coastal flooding, and hurricane force wind.

Avoidance or alleviation of the adverse impacts of hazard necessitates their clear recognition, qualification of the processes involved, accurate assessment of associated risk, an avoidance or technologic mitigation. The first three steps require Earth system scientific and engineering investitions; the fourth involves preventive procedures such as redesigning and reinforcing buildings, bridges, and dams, and constructing all-weather shelters and seawalls. Absolutely crucial to the fourth, sociopolitical process is wide-spread public understanding and appreciation of the problems of natural hazards. Once the potential danger properly assessed, mitigation can take place through the implementation of engineering solutions, the optimization of wise land use, effective public education, and continuous planning for emergencies. However, effective implementation of our scientific knowledge and engineering capacities requires widespread public understanding and support, something that is largely lacking at present around the world.

From W.G. Ernst (ed.)Earth Systems: Processes and Issues.

Cambridge University Press, 2000

Exercise 2. Translate from Russian into English

, , , , , , , , , () , (), , , , , , , , , , ,

Exercise 3. Add to the following adjectives

the appropriate negative prefixes, translate them

Perceptible, wise, exorable, lucky, expected.

Exercise 4. Find the words with the similar meaning in the text

To change, human-induced, to explain, danger, nearly, proper, negative, to climb, calamitous.

Exercise 5. Translate the following word groups

Hurricane force wind, imperceptible mantle circulation, mortality statistics, lightning-strike forest fires, all-weather shelter, wise land use, dam failure, hazard-prone environment, fluid envelopes, solar energy sink, solar energy input.

Exercise 6. Find the names of all disasters mentioned in the text

  • Give your own definitions to them;
  • Give examples of them (place, date, deaths)

Exercise 7. Match the beginning of the sentences with their endings

Beginning of the sentence

End of the sentence


As populations grow,


the ferocity and number of tropical storms will also rise, coastal erosion and flooding will accelerate.

Beginning of the sentence

End of the sentence


Because the Pacific Ocean is the worlds largest solar energy sink,

their expansion into, and utilization of, hazard-prone, marginal environments increases; consequently, the overall risk is heightened


If global temperatures continue to climb as a consequence of an intensifying greenhouse effect,


mitigation can take place through the implementation of engineering solutions, the optimization of wise land use, effective public education, and continuous planning for emergencies.


Once the potential danger properly assessed,


typically act of God


Each natural disaster is viewed as a unique event,


the underlying reasons accounting for geologic hazards are much less obvious.


Though climatic hazards are well-understood phenomena,


this basin is the site of the most devastating tropical storms and ocean-induced droughts.

Exercise 8. Answer the questions

  • 1. Why do natural hazards boggle the mind?
  • 2. What is hazard?
  • 3. What types of hazards are there?
  • 4. What are the examples of technogenic hazard?
  • 5. What impact does environment and loss of biodiversity have?
  • 6. What impact does Solar radiation have on the Earth?
  • 7. What processes are responsible for the differential motions of lithospheric slabs?
  • 8. What are the consequences of intensifying greenhouse effect?
  • 9. How do humans view natural disasters?
  • 10. How does the population grow influence the hazard risk?
  • 11. What processes lie beyond the limits of human ability to change them?
  • 12. What should be done to minimize the danger of hazards?
  • 13. What does the avoidance or alleviation of the hazard impact necessitate?
  • 14. What preventive procedures does the fourth step involve?
  • 15. Why does implementation of scientific knowledge and engineering capacities require widespread public understanding and support?

Discuss the following questions:

1. Which of the natural disasters learnt in the Unit seems most easily mitigated in terms of time? Money? Decreased threat to life? Ease of public awareness and willingness to plan for mitigation? Which appears to be most intractable, and why?

  • 2. In a region with which you are familiar, identify three geologic and/or climatic hazards. Pick one and, as spokesperson for the local Natural Hazards Mitigation Board, indicate how you would proceed in order to alleviate its dangers to the populace. What obstacles might hinder the adoption of your recommendations by local decision makers?
  • 3. Why is the Circum-Pacific region at significantly greater risk from natural disasters than most other areas - for example, the Atlantic coast? What special precautions would you make with regard to buying a house or starting up a business in the specific Pacific Rim location?
  • 4. Describe and justify the emergency plans you would recommend for your family and for your community in order to survive a geologic catastrophe if you resided in one of the following cities: Hilo (Hawaii), Tokyo (Japan), Los-Angeles (California), Dallas (Texas), Santiago (Chile), London (England). Identify the hazards, their attendant risks, and the likelihood and magnitude of potential damage.
  • 5. Earthquake forecasts generally consist of four elements: likelihood, location, intensity, and timing of the seismicity. Compare the specific societal value to the citizens of San-Francisco of the following predictions of an impending magnitude.

Contradictions in the interactions within system nature - technosphere-society

  • inability of the nature to meet in hill scale the growing demands of society
  • exesive usage of natural resources at limited abilities for restoration
  • aggravation the science-technical progress dilemma: high rates of technosphere development in XX century and outstanding achievements (nuclear, space, aviation on one hand and appearance and growing of potential and real threats for mankind

Texts for self-study Read the texts and do the tasks. Text 1. Technogenic Hazards

Development of technogenic sphere has resulted in the two directly opposite consequences:

On the one hand, great results are achieved in electron, atomic, cosmic, aviation, power, and chemical industries as well as in biology, genetic engineering, providing the humankind with opportunity to reach the crucially new levels in all spheres of life and production.

On the other hand, there appear previously unseen potential and real hazards and danger for a man, environment, and buildings not only in time of war but also in peace time.

These hazards appear in recent decades under the impact of great technogenic catastrophes on the enterprises of different profiles: nuclear (the USSR - Chernobyl, economic damage is about 400 bln. $, the USA - Trimale Island, economic damage is about 100 bln. $ etc.), chemical (India, Italy etc.); cosmic and aviation (the USA - Challenger, the USSR - rocket accidents at starts etc.); pipeline and transport systems and others.

Only in Russia there are about 100 000 dangerous enterprises. Nearly 2300 among them are nuclear and 3000 chemical plants of high hazard. In nuclear industry about 1013, but in chemical about 1012 of lethal toxodoses are concentrated.

The statistic analysis of accidents and catastrophes in Russia made by the State Safety Service shows that the number of fatal cases has increased by 10-25 %, and in some industries, for example in aviation - by 50 % annually. Thus, according to the data of RF Emergency Control Ministry in 2001 - 617 accidents of technogenic nature took place (apart from accidents with transport and industrial injuries) in which 3309 workers were injured, 1157 died. Economic damage because of accidents and catastrophes is constantly increasing, though not so drastically.

There is a shift of accident consequences towards the increase in the number of fatal cases at the relative stabilization of economic losses due to direct damage from accidents and recovery efforts. This phenomenon is observed against the decline in primary production and decrease in the number of potentially hazardous units. Hence, the specific incident rate for hazardous units is growing fast over the recent years.

Decline of industrial production, engineering and transport, decrease in the number of potentially hazardous units has improved the environmental conditions in general, but at the same time there appear a very dangerous tendency to the growth of portion and degree as well as absolute number of the severest accidents and catastrophes, which add social and physiological factors to usual economic losses, the former being sometimes of greater importance than economic factors.

The situation is worsened by the fact that most of the potentially hazardous units and industries are characterized by running out the project reserves and lifespan. Further operation results in sharp increase of failures. Shutting down the potentially dangerous units running out the reserves and lifespan poses a new and complex, scientific, economic, and social problem, the solution of which could not be avoided by the humankind.

Of no less concern is the problem of estimation of remaining reserves and lifespan. The problem is observed in other branches of industry including transport and construction. The life length of machines and equipment in the primary industries amounts: less than 10 years - 50 %, from 10 to 20 years - 30 %, more than 20 years - 20 %.

Thus, a large number of foreign and domestic equipment with running- out lifespan and without calculated lifespan operates at chemical, petrochemical, refinery enterprises. Besides, there is an obvious tendency to the growth of failure (including emergencies) due to the reasons conditioned by the old age and installation damage.

In Russia the systems of main pipelines (MP) of more than 200 000 klm. length, having about 6000 technically sophisticated surface units of extra hazard operate: compressor, pumping, and gas-distribution plants, tank batteries. Accident risk at MP plants is of rather high level and has a tendency to growth: the number of accidents in 1996 increased by 40 % in comparison with 1995. The aging processes of pipelines (certain pipelines operate more than 40 years) are characterized by decrease in reliability due to metal corrosion and fatigue, defects of technological and operational origin (a kind of crimp, buckle, undercut and others). 40 000 kilometer of pipelines and 25 % oil pipelines have run out their calculated lifespan.

The following data indicate the range of economic losses in technogenic accidents. These data include the analysis of 170 accidents with maximum economic losses over 30-years period (up to 1991), taken place in the field of mining, transport, and refining of hydrocarbons. Out of 170 accidents 123 took place in the course of every-day operation of enterprise, 43 - during the period of shutdown, start-ups, and repair. In this case the average damage of accidents in everyday operation is 1.5 times less than in accidents in the periods of shutdowns and start-ups.

Table 4.1

Distribution of economic losses in terms of accident processes types


of accident

Per cent of damage

Total number of accidents

Average damage per an accident, min. $





Cloud explosions
















Table 4.2

Distribution of economic losses in terms of accident types at various enterprises




Cloud explosions





31 %


Oil-chemical plants










Gas-processing plants





Other plants





Table 4.3

Distribution of economic losses in terms of the causes of accidents

Accident cause

Per cent of losses

Average damage, min. $

Mechanical destructions



Operational error



Unknown cause



Breach of operation order



Natural disasters



Project error






Table 4.4

Distribution of economic losses in terms of the types of equipment, at which the accident failure took place


Loss percentage

Average damage, min. $




Reservoirs, tanks






Other installation






Sea crafts



Unknown equipment






Heat exchange units



Surface casings



Heating boilers




a) Analyze technical, social, and economic causes of increase in number of technogenic accidents and catastrophes.

b) Make conclusion on distribution of economic losses of technogenic accidents and catastrophes depending on the type of accident processes and equipment used, causes of accidents, types of industrial processes using Tables 4.1 - 4.4.

Text 2. Methods of Qualitative Hazard Analysis

Hazards analysis can get pretty sophisticated and go into much detail. Where the potential hazards are significant and the possibility for trouble is quite real, such detail may well be essential. However, for many processes and operations - both real and proposed - a solid look at the operation or plans by a variety of affected people may be sufficient. The easiest and possibly most effective method is using the step-by-step process of the Job Hazard Analysis (JHA).

WHAT - IF Checklist: The what - if checklist is a broadly-based hazard assessment technique that combines the creative thinking of a selected team of specialists with the methodical focus of a prepared checklist. The result is a comprehensive process hazards analysis that is extremely useful in training operating personnel on the hazards of the particular operation.

The review team is selected to represent a wide range of disciplines - production, mechanical, technical, safety. The team is then provided with basic information on hazards of materials, process technology, procedures, equipment design, instrumentation control, incident experience, previous hazard reviews, and so on. A field tour of the process is also conducted at this time, assuming the process is in operation.

The review team methodically examines the process from receipt of raw materials to delivery of the finished product to the customer's site. At each step the group collectively generates a listing of what - if questions regarding the hazards and safety of the operation. When the review team has completed listing its spontaneously-generated questions, it systematically goes through a prepared checklist to stimulate additional questions.

Subsequently, answers are developed for each question. The review team then works to achieve a consensus on each question and answer. From these answers, a listing of recommendations is developed specifying the need for additional action or study. The recommendations, along with the list of questions and answers, become the key elements of the hazard assessment report.

Hazard and Operability Study (HAZOP): HAZOP is a formally structured method of systematically investigating each element of a system for all of the ways in which important parameters can deviate from the intended design conditions to create hazards and operability problems. The hazard and operability problems are typically determined by a study of the piping and instrument diagrams (or plant model) by a team of personnel who critically analyze the effects of potential problems arising in each pipeline and each vessel of the operation.

Pertinent parameters are selected - for example, flow, temperature, pressure, and time. Then the effect of deviations from design conditions of each parameter is examined. A list of key words such as more of, less of, none of, part of, are selected for use in describing each potential deviation.

The system is evaluated as designed and with deviations noted. All causes of failure are identified. Existing safeguards and protection are identified. An assessment is made weighing the consequences, causes, and protection requirements involved.

Failure Mode and Effect Analysis (FMEA): The failure mode and effect analysis is a methodical study of component failures. This review starts with a diagram of the process that includes all components which could fail and conceivably affect the safety of the process. Typical examples are instrument transmitters, controllers, valves, pumps, and rotometers. These components are listed on a data tabulation sheet and individually analyzed for the following:

  • Potential mode of failure ... open, closed, on, off, leaks, etc..
  • Consequence of the failure.
  • - Effect on other components.
  • - Effect on whole system.
  • Hazards class ... high, moderate, low.
  • Probability of failure.
  • Detection methods.
  • Compensating provision/remarks.

Multiple concurrent failures are also included in the analysis. The last step is analysis of the data for each component or multiple component failure and development of a series of recommendations appropriate to risk management.

Fault Tree Analysis:

A fault tree analysis is a quantitative assessment of all of the undesirable outcomes, such as a toxic gas release or explosion, which could result from a specific initiating event. It begins with a graphic representation (using logic symbols) of all possible sequences of events that could result in an incident. The resulting diagram looks like a tree with many branches - each branch listing the sequential events (failures) for different independent paths to the top event. Probabilities (using failure rate data) are assigned to each event and then used to calculate the probability of occurrence of the undesired event. A simple example of a fault tree analysis chart is shown below.

  • 1. Answer the questions:
  • 2. What is job hazard analysis?
  • 3. What does broadly-based hazard assessment technique combine?
  • 4. How is the review team selected?
  • 5. What is hazard and operability study?
  • 6. What is failure mode and effect analysis?
  • 7. What is fault tree analysis?
  • 2. Put the operations into logical order according to the text

a) The team is provided with basic information on hazards of materials, process technology.

b) The review team is selected to represent a wide range of disciplines - production, mechanical, technical, safety.

c) The recommendations are developed.

d) The review team methodically examines the process from receipt of raw materials to delivery of the finished product to the customer's site.

e) When the review team has completed listing its spontaneously- generated questions, it systematically goes through a prepared checklist to stimulate additional questions.

f) At each step the group collectively generates a listing of what - if questions regarding the hazards and safety of the operation.

g) A field tour of the process is also conducted at this time, assuming the process is in operation.

h) Answers are developed for each question.

Text 3. Sunspots and Earthquakes

Civilization's interest in predicting the location and time of damaging earthquakes is obvious. The potential for devastation of property that otherwise could be secured, and the loss of life that otherwise could be prevented, are powerful reasons to find predictive factors.

Some scientists have become aware of a correlation between sunspots and Earthquakes and want to use the sunspot data to help predict earthquakes. The theory is that an intensification of the magnetic field can cause changes in the geo-sphere. The NASA and the European Geosciences Union have already put their stamp of approval on the sunspot hypothesis, which suggests that changes in the sun-earth environment affect the magnetic field of the earth that can trigger earthquakes in areas prone to it. It is not clear how such a trigger might work.

In the Journal of Scientific Exploration, Vol. 17, No. 1, pp. 37-71, 2003, there is an excellent report that addresses the more down-to-earth problems facing geophysicists trying to understand earthquakes. The paper is titled, Rocks That Crackle and Sparkle and Glow: Strange Pre-Earthquake Phenomena, by Dr. Friedemann T. Freund, a professor in the Department of Physics, San Jose State University, and a senior researcher at NASA Ames Research Center. Dr. Freund writes, Many strange phenomena precede large earthquakes. Some of them have been reported for centuries, even millennia. The list is long and diverse: bulging of the Earths surface, changing well water levels, ground-hugging fog, low frequency electromagnetic emission, earthquake lights from ridges and mountain tops, magnetic field anomalies up to 0.5 % of the Earths dipole field, temperature anomalies by several degrees over wide areas as seen in satellite images, changes in the plasma density of the ionosphere, and strange animal behavior. Because it seems nearly impossible to imagine that such diverse phenomena could have a common physical cause, there is great confusion and even greater controversy.

Freund outlines the basic problem, Based on the reported laboratory results of electrical measurements, no mechanism seemed to exist that could account for the generation of those large currents in the Earths crust, which are needed to explain the strong EM signals and magnetic anomalies that have been documented before some earthquakes. Unfortunately, when a set of observations cannot be explained within the framework of existing knowledge, the tendency is not to believe the observation. Therefore, a general malaise has taken root in the geophysical community when it comes to the many reported non-seismic and non-geodesic pre-earthquake phenomena... There seems to be no bona fide physical process by which electric currents of sufficient magnitude could be generated in crustal rocks.

Freund makes an excellent attempt to explain all of the phenomena in terms of rock acting like a p-type semi-conducting material when placed under stress. For example, the emission of positive ions from the Earths surface may act as nuclei for the ground-hugging fog that sometimes occur prior to earthquake activity. And although the surface potential may only be in the 1-2-Volt range, the associated electric field can reach hundreds of thousands of Volts per centimeter, enough to cause corona discharges, or earthquake lights. Thermal anomalies seen from space before an earthquake may be due to the emission of infra-red light where the semi-conductor charge recombines at the surface. Disturbed animal behavior may be due to the presence of positive ions in the air.

As Freund says, this theory places an explanation in the realm of semiconductor physics, which means that geoscientists are not the best people to judge it. That explains why the paper appears in a speculative journal. Freund laments, the peer review system often creates near-insurmountable hurdles against the publication of data that seem contrary to long-held beliefs. Freund has identified a source of charge in stressed rocks that was not believed possible. He says,

. .once fully told and understood, the story [of p-holes] is basically so simple that many mainstream geoscientists are left to wonder why it has taken so long for them to be discovered. If they are so ubiquitous as they appear to be, why did p-holes go unnoticed for over a hundred years? Confronted with this question, by a twist of logic, many 'mainstreamers' succumb to the impulse to reject the p-hole concept out of hand.

The difficulties encountered in the connection with p-holes are similar to others that have punctuated the history of science. The discovery of the p- holes as dormant yet powerful charge carriers in the Earths crust calls for a new paradigm in earthquake research and beyond. More often than not, any call for a new paradigm elicits opposition. Therefore, I close with a quote from the philosopher Arthur Schopenhauer, who ventured to say: all truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.

If Freund has a problem getting such a simple idea accepted, how much more difficult is it going to be to get both astronomers and geoscientists to accept that the Earth is a charged body in an Electric Universe?

The missing link between the sunspots and earthquakes is the fact that the electric discharges on the Sun that cause sunspots also affect the Earth's ionosphere. The ionosphere forms one plate of a capacitor, while the Earth forms the other. Changes of voltage on one plate will induce movement of charge on the other. But unlike a capacitor, the Earth has charge distributed beneath the surface.

And if the subsurface rock has become semi-conducting because of stress, there is an opportunity for sudden electrical breakdown to occur through that rock. The mystery of how the current is generated is solved and the link with sunspots exposed. Subsurface lightning causes earthquakes! Seismic waves are the equivalent of the rumble of thunder. The energy released may be equivalent to the detonation of many atomic bombs but only a small proportion needs to come from the release of strain in the rocks. Most of it comes from the Earth's stored internal electrical energy.

The latest issue of the IEEE journal, SPECTRUM, features an article based on Freund's work that looks at ways of predicting earthquakes. Once again, it seems that scientific advances fare better today in the hands of electrical engineers.

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