Geo-Targeting Performance of Wireless Emergency Alerts in Imminent Threat Scenarios

Volume 1: Tornado Warnings

A significant long-standing challenge for imminent threat alert originators (AOs) at all levels of government is how to quickly communicate warning messages to people in danger, while avoiding to warn those not at risk. Providing effective warnings of an imminent threat, such as a dangerous tornado, can save lives. Ideally, people can take shelter before the tornado strikes if they are provided enough warning time.

People may receive irrelevant warnings and suffer from over-alerting, however. If over-alerting occurs, people’s lives can be disrupted; they may decide the warnings they receive are not accurate and may ignore later warnings that actually apply to them. Several terms have been coined to describe the impact of over-alerting: warning fatigue or warning complacency. Warning fatigue has occurred in highly destructive and deadly tornadoes. People ignored warnings delivered by sirens because the sirens had sounded so many times on past occasions when no tornado appeared. The sirens have also been sounded over too large of an area in past tornadoes (over county-wide areas), and included areas where the public was not threatened.

Volume 2: Earthquake, Tsunami and Radiation Warnings

A significant challenge for emergency managers and Alert Originators (AOs) is how to warn people in danger quickly, and avoid warning people not at risk. Providing effective warning of an imminent threat, such as an earthquake or tsunami, can save lives. People can take shelter or move to higher ground if they have enough warning time. If people frequently receive irrelevant warnings, however, they may choose to ignore later warnings that do apply to them. Several terms have been coined for this ― warning fatigue and warning complacency. Over-alerting can lead to warning fatigue. Geo-targeted Wireless Emergency Alerts (WEAs) can help reduce over-alerting and alert failures, and increase warning effectiveness.

This study examines how WEA can be used to warn the public in three potentially deadly scenarios:

• A large destructive earthquake;
• A Tsunami ; and
• A terrorist detonation of nuclear weapon in an urban area.