Complex sentence: The 2011 Tōhoku earthquake was somewhat larger than the predicted event, but occurred in the same area as the 869 earthquake and caused major flooding in the Sendai area.
Split into simpler sentences: The 2011 Tōhoku earthquake fulfilled the prediction but was somewhat larger than the predicted event. However it occurred in the exact same area as the 869 earthquake and caused major flooding in the Sendai area.