Complex sentence: The earthquake was rated 6.4 on the moment magnitude scale, and had a maximum perceived intensity of IX ("Violent") on the Mercalli intensity scale, though this relatively high intensity rating did not represent the majority of damage that was experienced.
Split into simpler sentences: The earthquake was rated 6.4 on the moment magnitude scale, and had a maximum perceived intensity of IX ("Violent") on the Mercalli intensity scale. However, this relatively high intensity rating did not represent the majority of damage that was experienced.