Technological advancements in optical fiber have significantly improved tsunami early warning systemTsunami Early Warning Systems (TEWS) (TEWS). There are two techniques that have recently emerged, such as fiber Bragg grating (FBG) sensorsFiber Bragg Grating sensor and distributed acoustic sensing (DAS). These technological improvements make the detection of changes in pressure simpler in order to understand tsunamiTsunami dynamics better and thus improve the accuracy of early warnings. While FBG sensors are good in monitoring these changes in pressure, DAS excels in detection of seismic waves that cause fast alerts of undersea earthquakes. In the proposed method, an FBG-based model is developed, and its mathematical analysis is conducted to evaluate the FBG output corresponding to different strain variations, which contribute to the occurrence of a tsunami. The ultimate end is to provide protection to seashore cities from the dreadful effects of a tsunamiTsunami on buildings and human beings. The introduction of optical fiber-based systems would not only make seismic event detection faster and enhanced but also help in disaster preparation.