Samoan Islands with black sand beaches. The highest peak is Mt. Silisili, on the island of Savai'i, one of the highest peaks in Polynesia at . The highest point in American Samoa is on Ta’u, Lata Mountain, at . The two large islands of Upolu and Savai'i in Samoa, are among the largest of Polynesian islands, at and , respectively, exceeded in size only by the two main islands of Fiji and the Hawaiian islands of Hawaiʻi and Maui. The island of Upolu is more populated than Savai'i. The next largest island is Tutuila, where the city and harbor Pago Pago (population
Hawaiian Islands there was a 6.9 earthquake in the zone of volcanic activity from Kīlauea. Earthquakes are monitored by the Hawaiian Volcano Observatory run by the USGS. The Hawaiian Islands are subject to tsunamis, great waves that strike the shore. Tsunamis are most often caused by earthquakes somewhere in the Pacific. The waves produced by the earthquakes travel at speeds of and can affect coastal regions thousands of miles (kilometers) away. Tsunamis may also originate from the Hawaiian Islands. Explosive volcanic activity can cause tsunamis. The island of Molokai had a catastrophic collapse or debris avalanche over a million years ago; this