Natural Warning Signs 1. Severe ground shaking from local earthquakes may cause tsunamis. 2. When a tsunami approaches a shoreline, water might be taken from the coast, exposing the ocean floor, reefs and fish. 3. An approaching tsunami creates a loud "roaring" sound.
Technological Warning Signs 1. Scientists use tsunami alarm systems to detect oncoming tsunamis. 2. Tsunami warning centers use technology to communicate official warnings, such as: sirens, television, and internet warning messages.