The tsunami run-up was only in areas in the state of Tamil Nadu shielded by the island of Sri Lanka but was in coastal districts such as Nagapattinam in Tamil Nadu directly across from Sumatra. On the western coast, the runup elevations were at Kanyakumari District in Tamil Nadu and each at Kollam and Ernakulam districts in Kerala. The time between the waves ranged from about 15 minutes to 90 minutes. The tsunami varied in height from to based on survivors' accounts. The tsunami travelled at its maximum inland at Karaikal, Puducherry. The inundation distance varied between in most areas, except at river mouths, where it was more than . Areas with dense coconut groves or mangroves had much smaller inundation distances, and those with river mouths or backwaters saw larger inundation distances. Presence of seawalls at the Kerala and Tamil Nadu coasts reduced the impact of the waves. However, when the seawalls were made of loose stones, the stones were displaced and carried a few metres inland.