The world’s longest continuous volcanic eruption is marking its 28th anniversary tomorrow.

Kilauea Volcano’s east rift zone began erupting on Jan. 3, 1983, and has continued uninterrupted since.

A second, simultaneous eruption began at Kilauea’s summit on March 19, 2008.

The Hawaiian Volcano Observatory, along with Hawaii Volcanoes National Park, Hawaii County Civil Defense and the University of Hawaii at Hilo, plan to mark the milestone by hosting public lectures, guided hikes and other activities throughout January.

Among upcoming activities:

» On Saturday, Don Swanson, a U.S. geologist who witnessed the first two years of Kilauea’s 1969-1974 east rift zone eruption, will share his experiences and talk about volcanic features on a 3-mile guided hike to Mauna Ulu. The hike is free, but park entrance fees apply. Hikers should wear sturdy shoes, bring drinking water and snacks, and be prepared for cool, rainy weather.

Registration is not required. Meet at 9 a.m. sharp at the Mauna Ulu parking area on Chain of Craters Road in Hawaii Volcanoes National Park.

» An explosive eruption that killed more than 80 and possibly several hundred people on Kilauea’s slopes 220 years ago will be the topic of a presentation Friday at UH-Hilo. Swanson will give the free presentation on the 1790 eruption at 7 p.m. in Wentworth Hall 1 on the UH-Hilo campus, 200 W. Kawili St. The 1790 blast was Kilauea’s largest explosive eruption in 1,000 years. Swanson says his findings provide a sketch of what can be expected during Kilauea’s next violent explosive eruption, and "the picture isn’t pretty."

Meanwhile, Civil Defense Administrator Quince Mento told the Hilo Tribune-Herald recently that the county’s viewing area is being extended over newly hardened lava, which will provide a better view than had been available recently.

Kilauea continued to erupt at two locations yesterday.

On the east rift zone, incandescent spots and minor lava flows were active within Puu Oo Crater and the Nov. 29 breakout continued to host scattered breakouts, the lowest advancing to within 640 feet of the end of Highway 130.

At the summit, conditions were unchanged, with slowly rising lava deep within a vent inset within the east wall of Halemaumau Crater. This lava lake circulated while its level rose and fell and produced a glow visible overnight from the Jaggar Museum.

Officials say no lava flows are entering the ocean and no homes are in immediate danger.

A magnitude-2.4 earthquake shook Kilauea at 10 p.m. Tuesday, with an epicenter 3 miles southeast of the summit. A magnitude-2.0 earthquake occurred at 2:08 p.m. Wednesday 3 miles southwest of the summit. A magnitude-2.9 quake rattled the south flank at 3:49 a.m. Thursday.