Davidof, Pyramid, Lopy and Khvostof
- ISS005-E-18287
- 23 October 2002
- 00:44 UTC
Situated within the Rat Islands group between the larger islands of Segula (6 km to the west, across the Khvostof Pass) and Little Sitkin (5 km to the east, across the Little Sitkin Pass) are the four small islands of Davidof (right side of the above image), Pyramid (centre), Khvostof (left) and Lopy (top). Together with Segula and Little Sitkin the islands form a tight grouping of islands located northwest of Amchitka and east of Kiska.
The islands are thought to be all that remains of an ancient twin-coned volcano that was largely destroyed in a catastrophic eruption during the late Tertiary period — Davidof, Lopy and Pyramid are remnants of the ancient caldera rim; Khvostof is a remnant of the western cone.
Khvostof's western shores rise steeply (marked by dark shadow in the image) from the sea, reaching a height of 265 m (at the prominent intersection of ridges), before forming a relatively flat interior plateau that slopes more gently to the lower, but still steep, slopes of the east, north and south.
Davidof, on the east, is the largest of the islands. Like Khvostof, its steep rocky shores rise to an interior plateau — although much narrower than that of Khvostof; maximum elevations on Davidof rise to 328 m in the southwest (this point is prominently marked in the above image) and to 280 m in the northeast. Much of its coastline consists steep slopes or beaches of boulder and pebbles; the Crater Bay coast on the southwest contains sandy beach.
The two smallest islands of the group are Pyramid Island and Lopy Island. Pyramid Island (rising to 164 m above sea level) lies within Crater Bay; Lopy Island, located off the northwestern tip of Davidof, rises to 107 m.
image: earth sciences and image analysis laboratory, nasa johnson space center
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