During the earthquake several buildings and infrastructure were totally destroyed. Many people were killed and there was a Tsunami watch for the island. The earthquake measured on the scale?​

Richter scale

Explanation:

The earthquake is measured on Richter scale which measures the magnitude of an earthquake. The Richter scale measures the largest amplitude on the recording, but other magnitude scales measure different parts of the earthquake. The USGS currently used Moment Magnitude scale for measuring earthquake magnitudes. These scales are present in every location where tectonic plates meets or regions surrounded these plates.