Service overview
Geology, geophysics, GIS, remote sensing, hydrology, seismology and hazard modelling. This service is part of that division and is scoped individually around what you need to learn, decide or publish.
Natural hazards such as earthquakes, landslides and floods cannot be predicted precisely, but their frequency and consequences can be described statistically. Hazard modelling therefore deals in probabilities, scenarios and susceptibility maps, and its credibility depends on the quality of catalogues, the choice of models and honest statements of uncertainty.
A fundamental distinction is between hazard, the likelihood and intensity of a phenomenon, and risk, which combines hazard with exposure and vulnerability. Many studies produce hazard or susceptibility maps and call them risk maps. This service supports analysis of seismic data and hazard modelling with careful terminology, statistically sound methods and clear limits on what the outputs mean.
If you plan to publish the outcome, see manuscript & publication support, for example computational & simulation manuscripts or original research article writing.
What this service covers
Problems this service can address
- Incomplete catalogues and uncertain recurrence
- Combining hazard with exposure and vulnerability
- Communicating probabilistic results
Methods and analytical approaches
- Seismic catalogue statistics
- Probabilistic hazard concepts
- Landslide and flood susceptibility modelling
- Scenario-based analysis
Applications
- Seismic hazard research
- Landslide susceptibility mapping
- Hazard-scenario studies
Relevant engineering disciplines
Scope, inputs and deliverables
Scope of work
- Definition of the technical question, system boundary and success criteria
- Analysis, modelling or data work appropriate to your inputs
- Results with stated assumptions and limits of validity
- Documentation in a form suitable for reports or publication
- Feasibility check on: catalogue or hazard data
Typical inputs required from you
- Catalogue or hazard data
- Study region and objectives
- Exposure data, if risk is considered
Deliverables
- Hazard analysis report
- Maps and scenario results
- Uncertainty statement
Highly specialised requests are first checked for feasibility from this information. Please do not send confidential data through the public form; describe it first and agree secure transfer afterwards.
Project workflow and method
- 01Enquiry and requirement assessment
- 02Technical scoping and proposal
- 03Execution
- 04Quality review and delivery, with an agreed round of revisions
Read the full project workflow.
In depth: how the work is done
Seismic catalogue statistics
Earthquake catalogues need checks for completeness, magnitude homogeneity and declustering to separate mainshocks from aftershocks. The Gutenberg-Richter relation describes the frequency-magnitude distribution, with b-value estimated by maximum likelihood and its uncertainty reported. Catalogue completeness varies in time and space, and analysing incomplete data biases rates.
Probabilistic hazard concepts
Probabilistic seismic hazard analysis combines source zones or faults, earthquake recurrence, ground-motion models and site conditions to give annual exceedance probabilities of ground-motion intensity. Logic trees express epistemic uncertainty among alternative models. Results for long return periods rely on extrapolation. We explain the structure and test sensitivity, and we do not present research outputs as design values.
Landslide and flood susceptibility modelling
Susceptibility models relate mapped events to conditioning factors such as slope, lithology, rainfall and land cover using statistical or machine-learning methods. Validation uses independent events and spatially separate test areas, and measures such as the area under the ROC curve should be accompanied by an assessment of spatial autocorrelation. Susceptibility says where events are more likely, not when or how large.
Scenario-based analysis
Scenario analysis explores consequences of a specified event, for example a magnitude 7 earthquake on a given fault, with ground-motion fields and damage estimates. It is useful for planning and communication but depends on the chosen scenario and vulnerability models. We state assumptions and show variability among plausible ground-motion models.
Exposure, vulnerability and risk
Risk assessment combines hazard with inventories of assets and their vulnerability, often from fragility functions. Data on exposure are incomplete in many regions, and vulnerability functions are transferred from other contexts with uncertainty. We separate the components so each can be examined and avoid claims about losses beyond the quality of the inputs.
Communicating hazard information
Probabilities and return periods are easily misunderstood; for example, a hundred-year event can occur in consecutive years. Maps need legends explaining what the colours mean and what they do not. Research reports should state that outputs are not official hazard maps and do not support emergency decisions without review by responsible authorities.
Data sources and their limitations in hazard studies
Hazard studies draw on historical catalogues, instrumental networks, geological records, inventories of past events and remote-sensing products. Historical records are biased towards populated areas and recent periods; inventories may be incomplete for small events. Each source should be described with its coverage, completeness and error. Where data are sparse, expert judgement and logic trees can represent alternatives, but the judgement involved is documented and not hidden in parameters.
Validating hazard models
Validation of hazard models is difficult because rare events are few. Retrospective testing against past events, comparison of forecast rates with observed counts and cross-validation across regions give partial evidence. Where no validation is possible, the report says so and presents results as conditional on the model assumptions. This honesty helps users understand the strength of the information.
Ethical and social dimensions of hazard research
Hazard information affects real communities. Maps can alter property values, insurance and public perception, and errors can create false reassurance or unnecessary alarm. Researchers should consider how results will be used, engage with local authorities where possible and present limitations prominently. Uncertainty statements are not a disclaimer to avoid responsibility but information that helps users interpret the work appropriately.
Quality control and good practice
Quality-control approach
- Models and analyses are checked against hand calculations, published benchmarks or your data where available.
- Assumptions, boundary conditions and sources are listed in the deliverable.
- Units, symbols and terminology are checked for consistency.
- Limits of validity are stated; the work is research-level analysis, not certification.
Common pitfalls this service helps avoid
- Using incomplete catalogues. Rates are underestimated when small events are missed.
- Confusing susceptibility with risk. Susceptibility lacks information on exposure, vulnerability and event frequency.
- Random validation points near training points. Spatial autocorrelation inflates reported accuracy.
- Presenting research maps as official hazard maps. Official maps follow regulatory methods and review.
What good reporting looks like
A hazard report defines hazard, susceptibility or risk precisely, describes the data and completeness, the statistical or probabilistic methods, the model uncertainties, the validation, the results and sensitivity analysis and the limitations. It is not an official hazard assessment and must not be used for emergency management, land-use regulation or design without review by qualified authorities.
An illustrative scenario
Hypothetical example written for explanation. It is not a client case, a result or a testimonial.
Suppose a researcher builds a landslide susceptibility map using logistic regression. Random validation gives excellent performance, but a spatial block validation shows a considerable drop. The final map is presented with the block-validation results, a note that rainfall triggering was not modelled, and the clear statement that it indicates relative susceptibility, not probability of failure in a given year.
Questions to settle before you begin
- Is my catalogue complete for the magnitudes I analyse?
- Do I mean hazard, susceptibility or risk?
- How will I validate spatially?
- Which models represent epistemic uncertainty?
- What can my outputs not be used for?
Key terms
- Gutenberg-Richter law
- A relation between earthquake magnitude and frequency.
- Return period
- The average time between events of a given size.
- Logic tree
- A structure for combining alternative models with weights.
- Susceptibility
- Relative spatial likelihood of occurrence given conditions.
- Fragility function
- The probability of damage given an intensity measure.
Working together on Earth Sciences & Geosciences projects
Earth sciences engagements start with the dataset or field question: location, scale, sampling approach, measurement methods and the uncertainties in each. We ask for data tables, maps or logs in standard formats, the conceptual model you hold and any prior interpretations. Analyses make explicit how spatial and temporal sampling limits what can be concluded. Reports describe uncertainty and non-uniqueness, as in geophysical inversion, and separate observation from interpretation. Site-specific engineering or hazard decisions require qualified professionals and are outside the scope.
Frequently asked questions
Do you issue hazard assessments for regulation?
No. Our work is research-level analysis; formal hazard determinations are by authorised bodies.
Can you analyse an earthquake catalogue?
Yes, including completeness, declustering and b-value estimation.
Do you produce official hazard maps?
No. Official hazard assessment is performed by authorities and qualified experts.
Can you model landslide susceptibility?
Yes, with proper validation and clear statement of meaning.
Can you include climate change scenarios?
Scenario inputs can be included with uncertainty stated.
How is this service scoped and priced?
After your enquiry we review what you need, ask for missing information and send a written scope and quotation. Price depends on complexity, deliverables and timeline. See the project workflow.