Pallas Peak is located inside the ancient central building of Ketoi Volcano on the eastern edge of Ketoy Lake. The southwestern, older and higher (about 1000 m) part of the volcano forms an amphitheater open to the northeast, in which a young cone is located. The northeastern slopes of the latter descend to the atrio of the ancient caldera, and the southeastern slope, leaning against the wall of the amphitheater, is barely pronounced. The cone of Pallas Peak is somewhat elongated from southwest to northeast. The relative height of the cone above the level of Ketoy Lake is 320 m, the diameter of the crater of the inner cone is about 400 m. The walls of the crater abruptly break down, and at the bottom of it there is the Glazok crater lake with a diameter of 300 m. To the southwest from Pallas Peak to the shores of Ketoy Lake descends ancient, heavily overgrown lava flows. Numerous young lava flows extend eastward to the very shore of the ocean (up to 4.5 km). A series of lava flows from the crater of the inner cone extend northward, filling the atrio of the ancient caldera. On the northeastern slope of the cone there is a linear group of very powerful fumaroles.
Горшков Г.С. Вулканизм Курильской островной дуги / Отв. ред. Рудич К.Н. М.: Наука. 1967. 288 с.