1. There were more than 120 aftershocks with magnitudes greater than 5 on the Richter scale since Saturday.
2. Strong earthquakes with magnitudes over 7 separately rocked Pacific islands south of New Zealand and the US territory of Guam yesterday.
3. The regulation requires all cities exposed to tremors with magnitudes above 6 to consider earthquake prevention measures.
4. Falls of similar magnitudes are possible on the stock exchanges of countries including Spain and Italy.