1, cause: "5m wave" is a wave formed by the wind blowing the sea surface. When the wind blows over the sea, it will transfer energy to the sea and form waves. Waves have certain periodicity and directionality, and can spread in the ocean. "5m surge" is the vertical displacement of seawater caused by earthquake, submarine crustal movement or other factors. Surge is an aperiodic fluctuation, which is caused by tsunami or other ocean events caused by earthquake.

2. Wave characteristics: "5m wave" refers to the height of the wave, indicating that the vertical distance between the peak and the trough is 5m. The height of waves will be affected by wind speed, wind direction, wind duration and ocean depth. Waves propagate at a certain frequency and direction. "5m surge" refers to the height of surge, indicating that the vertical distance between surge peak and surge valley is 5m. The height of surge is higher than normal waves, because surge is an aperiodic fluctuation caused by a powerful energy source.