Heard Island is by far the largest of the group. It is a bleak and mountainous island located at . Its mountains are covered in glaciers; the island is 80% covered with ice. The glaciation of the island from its highest point right up to the sea consists of thick ice with ice cliffs along most of the coastline. It is dominated by Mawson Peak, a high complex volcano which forms part of the Big Ben massif. A July 2000 satellite image by the University of Hawaii showed an active long and wide lava flow trending southwest from the summit. Mawson Peak is one of only two active volcanoes in the Australian territory, the other being on McDonald Island. It is also one of the highest Australian mountains, surpassed only by peaks in the Antarctic territory. The island is in length at a point between the western edge of the Laurens Peninsula and the easternmost point of Elephant Spit. It is wide at a point between Saddle Point on the north coast and the Long Beach on the south coast. It has two circular volcanic cones, Big Ben and Mt Dixon, apart. Volcanic activity on the island has been noted since the mid-1980s, particularly on the southern part of the island which has resulted in the island's shape undergoing change and all wildlife disappearing; it is also reported that the size of the island has doubled and its height increased.