Burr Point is a headland on Augustine Island in Kamishak Bay, on the western margin of lower Cook Inlet, about 108 miles (174 km) north-northwest of Kodiak and 69 miles (111 km) southwest of Homer, Alaska. The uninhabited island has a nearly symmetrical central summit rising to 4,134 feet (1,260 m). Captain James Cook of the Royal Navy first discovered and named it “Saint Augustine Island” in 1778. The following year, Don Ignacio Arteaga of the Spanish Navy called it “Pan de Azucar,” or “sugar loaf.” In 1852, Captain Mikhail D. Tebenkov of the Imperial Russian Navy named it “Mount Chernoburoy,” from the Russian “chernyy” (black) and “buryy” (brown). Burr Point was reportedly named in 1914 by the US Coast and Geodetic Survey for the burr-like appearance of mounds along the volcano’s northeast coast. The volcano has erupted repeatedly in late-Holocene and historical times, typically producing high-energy debris avalanches of large angular clasts shed from summit domes, which form much of Augustine’s lower flanks.

Augustine Volcano began erupting on the flank of a small island of Jurassic clastic-sedimentary rock (about 201 million to 143 million years ago) before the late Wisconsin glaciation. The oldest known eruptions ranged from steam-driven olivine basalt explosions to highly explosive magmatic eruptions of dacite or rhyodacite pumice flows. Ash deposits as far away as Shuyak Island record eruptions between roughly 5,350 and 2,200 years before present (BP), with documented ash layers from 5,330 to 5,020 BP and 3,620 to 3,360 BP. Another ash layer in peat near Homer dates to about 2,275 BP. From 2,200 BP onward, eruptive products abundantly mantle the island, with numerous coarse debris avalanches sweeping beyond Augustine’s coast, most recently in 1883. That eruption triggered a 30-foot (9 m) tsunami that destroyed the village of English Bay (now Nanwalek) on the Kenai Peninsula and left the summit decapitated, later partially rebuilt by andesite domes from six subsequent eruptions. The 1883 debris avalanche buried the former shoreline and pushed the new one 1 mile (1.6 km) seaward; bathymetry shows it traveled an additional 1.8 miles (3 km) beneath the sea. Most material consisted of angular cobble-to-boulder fragments, with some clasts measuring 10 to 25 feet (3–8 m).

Since 1883, significant eruptions occurred in 1936, 1963, 1976, 1986 and 2006. In January and February 1976, explosive eruptions sent pyroclastic flows down several flanks, with the greatest volume on the north slope; dome growth in mid-April truncated the 1883 and 1935 domes, while repeated sloughing of the dome’s steep north edge produced lithic pyroclastic flows. From March to August 1986, a major eruption sent scores of pyroclastic flows down the north and northeast flanks, built a new summit dome and spread ash as far as Anchorage, some 180 miles (290 km) to the northeast. In January 2006, explosions burst from the 1986 summit dome; the largest pyroclastic flow, of dense pumice, swept to the lower north flank on January 28th, filling a shallow pond and burning off surrounding scrub alder—as in the two previous eruptions. A new summit dome grew that winter, draping lava flows over the upper north and northeast flanks, though the 2006 pyroclastic flows and lahars were far less extensive than in the three preceding eruptions. Read more about Augustine Volcano here and here. Explore more of Burr Point and Augustine Island here: