Tsunami Advisory
Overview
A tsunami advisory is one of the warning systems issued by the Korea Meteorological Administration when there is a high possibility of a tsunami occurring, or when a tsunami has already occurred and waves of a certain size are expected to reach the coast. A tsunami advisory is a lower warning level than a tsunami warning, and is typically issued when the earthquake magnitude is large or when submarine crustal deformation is detected. This warning plays a crucial role in helping the public evacuate quickly and minimize damage.
Main Content
Definition and Purpose of Tsunami Advisory
A tsunami advisory is a system designed to reduce casualties and property damage by issuing advance warnings when a tsunami is likely to affect coastal areas. It is usually issued when an undersea earthquake of magnitude 6.5 or higher occurs, or when a tsunami is generated by a submarine volcanic eruption or submarine landslide. Unlike a tsunami warning, a tsunami advisory can be issued even when the expected wave height is relatively low or when sufficient arrival time is not secured.
Issuance Criteria and Procedures
The Korea Meteorological Administration issues tsunami warnings based on the following criteria:
- Tsunami Advisory: Issued when an undersea earthquake of magnitude 6.5 or higher but less than 7.0 occurs, or when the earthquake magnitude is 7.0 or higher but the likelihood of a tsunami is low.
- Tsunami Warning: Issued when an undersea earthquake of magnitude 7.0 or higher occurs and a tsunami is confirmed, or when a tsunami height of 0.5 meters or more is expected.
The issuance procedure involves an automatic analysis system identifying the earthquake magnitude and location within 2 to 3 minutes of detection, and assessing the likelihood of a tsunami. Subsequently, the Korea Meteorological Administration immediately notifies relevant agencies (local governments, coast guard, fire departments, etc.) and disseminates the warning to the public via TV, radio, smartphone disaster text messages, and the internet.
Action Guidelines When a Tsunami Advisory is Issued
When a tsunami advisory is issued, the public should take the following actions:
1. Rapid Evacuation: Immediately evacuate from the coast to inland or higher ground. Since a tsunami can arrive within minutes to tens of minutes, do not delay.
2. Check Information: Continuously check the latest information through official channels such as TV, radio, and disaster text messages.
3. Prepare Vessels: Vessels in ports or at sea should immediately leave port and move to deep water, or find a safe anchorage.
4. Beware of Secondary Damage: Even after the tsunami passes, aftershocks or additional tsunamis may occur, so maintain evacuation until safety is confirmed.
Historical Cases of Tsunami Advisories
In South Korea, a tsunami advisory was issued for the east coast during the 2011 Tohoku earthquake in Japan. The tsunami generated by the magnitude 9.0 earthquake in Japan reached the east coast of South Korea, with waves of around 0.5 meters observed in some areas. This case served as an opportunity to review the response system when a tsunami advisory is actually issued. Additionally, during the January 2024 Noto Peninsula earthquake in Japan (magnitude 7.6), a tsunami advisory was issued for some areas of South Korea's east coast, leading to a commotion as many citizens evacuated.
Limitations and Improvements of Tsunami Advisories
Tsunami advisories must be issued within minutes of an earthquake, posing challenges between accuracy and speed. In particular, since the occurrence of a tsunami depends on the earthquake's magnitude and location, false alarms can occur. For example, during the January 2024 Noto Peninsula earthquake, the Korea Meteorological Administration issued a tsunami advisory, but the actual tsunami height was lower than expected, drawing criticism of overreaction from some quarters. Conversely, there have been cases where warnings were delayed despite a tsunami occurring, leading to greater damage, highlighting the need for continuous system improvement.
Latest Trends
Key trends related to tsunami advisories from 2024 to 2025 are as follows:
- Introduction of AI-based Prediction System: Since 2024, the Korea Meteorological Administration has been piloting an artificial intelligence (AI)-based tsunami prediction system. This system learns from historical earthquake data and tsunami propagation models to predict tsunami height and arrival time within one minute of an earthquake.
- Strengthened International Cooperation: Through collaboration with the Pacific Tsunami Warning Center (PTWC), real-time data is shared with Japan, the United States, and others. In 2025, a joint tsunami warning drill among South Korea, China, and Japan is planned.
- Expanded Public Education and Drills: Since 2024, a 'Tsunami Preparedness Week' has been held every March to strengthen evacuation drills and education for coastal residents. In particular, virtual reality (VR) evacuation training via smartphone apps has been introduced.
- Improved Warning Delivery System: From 2025, disaster text messages have been improved to include specific expected tsunami arrival times and heights. Additionally, multilingual support has been expanded to ensure the safety of foreign tourists.
Related Topics
- [[Tsunami]]
- [[Korea Meteorological Administration]]
- [[Disaster Warning System]]
- [[2011 Tōhoku earthquake and tsunami]]
- [[Tsunami Warning]]