Complex sentence: One of the oldest teletsunamis was reported in November 1755, when a major earthquake known as the 1755 Lisbon earthquake resulted in a teletsunami, which resulted in near-total destruction of Lisbon in the Kingdom of Portugal.
Split into simpler sentences: One of the oldest teletsunamis was reported in November 1755, when a major earthquake known as the 1755 Lisbon earthquake resulted in a teletsunami. This caused near-total destruction of Lisbon in the Kingdom of Portugal.