Where could I find the dataset for Geographical Hot Spots (Hurricanes, Tsunami, Earth quakes, Floods etc) associated with each countries?
Addressing partly your question:
The NOAA has a Significant Earthquake database that can be downloaded in CSV format. The dataset also indicates if the earthquake event was linked to a tsunami.
Once again a partial answer...
The Dartmouth Flood Observatory (now housed at the University of Colorado instead of Dartmouth) maintains a list of large remotely sensed flood events going back to 1985 with countries. Download the excel sheet to see the full set.