Introduction:
Forecasting tectonic hazards helps reduce risk. Scientists use different methods to predict earthquakes, volcanic eruptions and tsunamis with varying levels of success.

Forecasting and Predicting Tectonic Events

The Role of Prediction and Forecasting

Prediction refers to providing a specific time, location, and magnitude of a tectonic event, while forecasting gives probabilistic assessments over a timeframe. For tectonic hazards, exact prediction remains difficult, but forecasting is more achievable.

Scientists play an important role in both forecasting and mitigating the risks associated with tectonic hazards. Their contributions involve monitoring, modelling and communicating risk based on geophysical evidence.

Earthquake Forecasting

Forecasting earthquakes is the most uncertain among tectonic hazards due to the complex nature of crustal stress and fault behaviour.

Why Earthquake Prediction Is Difficult

• Earthquakes often occur without clear precursors.

• Stress builds gradually, but release is sudden and hard to track.

• Fault systems are complex and subsurface processes are hard to observe directly.

Methods Used in Earthquake Forecasting

• Seismic monitoring: Measures small foreshocks and tremors, but these do not always lead to major events.

A global map showing the locations of permanent seismometer stations in the Global Seismic Network, used to detect and locate earthquakes in real time. source

• Strain meters and GPS: Detect crustal deformation, which may indicate accumulating stress.

• Historical records and recurrence intervals: Used to identify patterns over time, especially along major faults.

• Seismic gap theory: Suggests that segments of faults that haven’t slipped in a long time are more likely to experience a large earthquake.

Despite these efforts, reliable short-term prediction remains scientifically elusive. Earthquake forecasting is typically probabilistic—stating the likelihood of an event within a given time period.

Volcanic Eruption Forecasting

Volcanic eruptions are more amenable to prediction due to the detectable physical changes that often precede them.

Techniques Used in Volcano Forecasting

• Seismology: Earthquake swarms beneath a volcano indicate magma movement.

• Ground deformation: Tiltmeters and GPS detect swelling caused by rising magma.

A cross-section of Kīlauea’s subsurface magma plumbing system, showing reservoirs and dikes whose inflation and deflation are monitored to forecast eruptions. source

• Gas emissions: Increased levels of gases such as sulphur dioxide (SO₂) can suggest magma nearing the surface.

• Thermal imaging: Detects heat anomalies in the ground or crater areas.

• Remote sensing: Satellites provide broad coverage of thermal, gas and ground changes.

These techniques allow scientists to develop eruption forecasts with reasonable accuracy, often providing days to weeks of warning, enabling evacuations and hazard preparations.

Tsunami Forecasting

Tsunamis are generally caused by undersea earthquakes at subduction zones, where one tectonic plate is forced under another. These events cause sudden vertical displacement of the sea floor, leading to wave generation.

Tsunami Prediction and Early Warning Systems

Although tsunamis cannot be predicted in advance of the triggering earthquake, early warning systems can detect them rapidly after they form.

• Seismometers: Identify undersea earthquakes and assess whether they are likely to generate tsunamis.

• DART buoys (Deep-ocean Assessment and Reporting of Tsunamis): Measure pressure changes in the ocean to detect tsunami waves.

• Tsunami Warning Centres: Analyse data and issue alerts to vulnerable coastlines within minutes of detection.

These systems are especially effective in the Pacific and Indian Oceans, though their success depends on communication speed, public awareness, and infrastructure readiness.

Accuracy Variation by Hazard Type

The accuracy of prediction and forecasting varies widely:

• Earthquakes: Poor short-term predictability; long-term forecasts possible for high-risk zones.

• Volcanoes: Good short-term forecasting due to observable precursors.

• Tsunamis: Prediction limited to post-earthquake detection; early warning systems can mitigate impact if implemented effectively.

The Importance of Location and Context

Geographical location plays a major role in forecasting effectiveness:

• Some regions are well-monitored (e.g. Japan, USA), while others lack infrastructure (e.g. many developing countries).

• Local geology affects the type and frequency of hazards—e.g. fast-moving subduction zones vs. stable continental interiors.

Additionally, population density, economic development and governance influence how well forecasting systems are implemented and how communities respond.

Scientific Contributions and Limitations

Scientists contribute by:

• Developing models of tectonic behaviour.

• Installing and maintaining monitoring equipment.

• Collaborating internationally on hazard forecasting systems.

• Educating governments and the public.

However, limitations include:

• Incomplete data in remote or poorly monitored regions.

• Uncertainty in interpreting signals, particularly for earthquakes.

• Financial and political constraints affecting monitoring and response.

Despite these challenges, scientific forecasting remains a critical tool in risk reduction and disaster preparedness.