Kīlauea is one of the world's most active volcanoes. Over the past 10 years, it has erupted in two places: the summit and Pu'u ‘Ō’ō
In April 2018, United States Geologic Survey (USGS) scientists observed increased pressure of the magma beneath Pu'u 'Ō’ō, and it caused the crater floor of Pu'u 'Ō’ō to rise. The summit you see before you also went through a period of increased inflation. On April 26, the lava lake overflowed into the crater floor at the summit and on the 30th, the crater floor of Pu'u 'Ō’ō collapsed. Two days later, the summit lava lake began to drop. USGS scientists detected a series of earthquakes moving east, signaling an intrusion of magma along the middle and lower East Rift Zone.
On May 3, the first fissure opened along the lower East Rift Zone in a residential subdivision. During the next three days, ten more fissures opened. By May 15, the number of fissures increased to 20. On May 19, lava flow fronts formed and moved to the ocean to the southeast. On May 29, huge lava flows from fissure 8 began to move northeast to Kapoho Bay. Over the next month, lava continued to flow toward the ocean and created a huge lava delta. This delta along with other ocean entries created about 875 acres of new land on the Big Island.
As the summit subsided and adjusted to withdrawal of magma, powerful earthquakes and ash explosions grew more frequent. The largest earthquake occurred on May 4 at 12:32 PM and was magnitude 6.9. The largest ash plume rose 30,000 feet above sea level on May 17. By June, the caldera floor before you began to rapidly collapse, dramatically and permanently changing the summit landscape.
From May through August, more than 80,000 earthquakes occurred in the area in which you are now standing, with 62 major collapse explosions. As a result, the crater you are now viewing increased in depth from 280 feet to approximately 1600 feet and the diameter more than doubled.
As of September 2018, lava flows covered 13.7 square miles of land. Over 700 homes have been destroyed and approximately 2000 people have been displaced.
Our thanks to the staff at Hawai'i Volcanoes National Park for allowing the placement of this Earthcache.
Questions:
1. What type of volcano is Kīlauea? How does it differ from other volcano types?
2. According to the plaque before you, what has happened here over the past 200 years?
3. Huge changes have occurred to the landscape before you, especially with regard to the caldera. Look about. Examine the walls of the caldera. What evidence do you see of the 2018 volcanic activity? Can you distinguish between old and new volcanic activity here?
4. From the vantage Point of the Volcano House, can you observe any steam vents?
5. How has the most recent activity affected accessibility to portions of the park, especially with regard to the trails, Crater Rim Drive, and overlooks? What is it about the proximity to the caldera of the Jagger Museum, Hawaiian Volcano Observatory, and Visitor Center that has affected their accessibility for your trip today?
5. OPTIONAL: Post a picture of your group at GZ.
For more information, see https://www.nps.gov/havo/planyourvisit/lava2.htm