earth science

Seismic risk

Seismic risk is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Seismic risk rather than just read about it. In short: Seismic risk or earthquake risk is the potential impact on the built environment and on people's well-being from future earthquakes. Seismic risk has been defined, for most management purposes, as the potential economic, social and environmental consequences of hazardous events that may occur in a specified period of time.

Key takeaways

Seismic risk belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Seismic risk to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Seismic risk from memory before moving on to harder problems.

Reference excerpt

Seismic risk or earthquake risk is the potential impact on the built environment and on people's well-being from future earthquakes. Seismic risk has been defined, for most management purposes, as the potential economic, social and environmental consequences of hazardous events that may occur in a specified period of time. A building located in a region of high seismic hazard is at lower risk if it is built to sound seismic engineering principles. On the other hand, a brick building on fill that is subject to liquefaction in a region of minor seismicity can be at higher risk. A subset is urban seismic risk. Risk determination and emergency response can also be determined through the use of an earthquake scenario.

Determination of seismic risk The determination of seismic risk is the foundation for risk mitigation decision-making, a key step in risk management. Large corporations and other enterprises (e.g., local governments) analyze their 'portfolio' of properties, to determine how to best allocate limited funds for structural strengthening of buildings, or other risk reduction measures such as emergency planning. In calculating the risk of each facility in the 'portfolio', potential life safety and economic losses due not only to structural damage, but also to equipment, contents and business interruption are considered. Public agencies (local, state governments and federal agencies) similarly analyze their portfolios. The interconnections of infrastructures such as water, road and highway, and electric power systems are also considered. Insurance companies routinely employ estimates of seismic risk in their operations to determine appropriate insurance rates, monitor over-accumulation of policies in a small area, and purchase reinsurance. A simplified method of calculating seismic risk for a given city, involves the use of a street survey. If you know the level of seismic hazard, the damage generally follows established patterns. Seismic risk is often determined using a seismic modeling computer programs which uses the seismic hazard inputs and combines them with the known susceptibilities of structures and facilities, such as buildings, bridges, electrical power switching stations, etc. The result gives probabilities for economic damage or casualties, for example the HAZUS computer program. While the results can be used as a general measure of seismic risk for types of buildings, the actual seismic risk for any individual building may vary considerably and will depend upon its exact configuration and condition. Acquiring and analyzing the specific data for an individual building or facility is one of the most expensive and daunting aspects of seismic risk estimation. Progress is made if one can calculate the 'fragility' or seismic capacity of the components within a structure. In 1999, ASTM produced guidelines for reporting seismic loss estimates on commercial properties, commonly known as probable maximum loss or PML reviews. These guidelines specify the scope of work, qualifications of the reviewer, and proper nomenclature for reporting loss estimates.

Reduction of seismic risk Seismic risk can be reduced by active programs that improve emergency response, and improve basic infrastructure. The concepts of earthquake preparedness can help plan for emergencies arising from an earthquake. Building codes are intended to help to manage seismic risk and are updated as more is learned about the effects of seismic ground motion on buildings. This type of active improvement of mitigation of damage from earthquakes is known as seismic retrofit. However, the changes generally do not immediately improve seismic risk in a community since existing buildings are rarely required to be upgraded to meet the revisions.

See also C. Allin Cornell Probabilistic risk assessment

Notes

Illustrations

Worked examples

Example 1 — a first encounter with Seismic risk

Start with the simplest possible case. Write down what Seismic risk claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Seismic risk before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Seismic risk ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Seismic risk

In research: Seismic risk appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Seismic risk in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Seismic risk is common in secondary-school and first-year university syllabi. It links to neighbouring topics Earthquake and seismic risk mitigation, so understanding it makes those chapters shorter.
In everyday life: Look for Seismic risk outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Seismic risk” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Seismic risk in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Seismic risk means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Seismic risk out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Seismic risk in simple terms?

Why does Seismic risk matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Seismic risk?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Seismic risk.