The Hawaiian Volcano Observatory (HVO) is an agency of the U.S. Geological Survey (USGS) and one of five volcano observatories operating under the USGS Volcano Hazards Program. Based in Hilo, Hawaii, the observatory monitors six Hawaiian volcanoes: Kīlauea, Mauna Loa, Kamaʻehuakanaloa (formerly Lōʻihi), Hualālai, Mauna Kea, and Haleakalā, of which, Kīlauea and Mauna Loa are the most active. The observatory has a worldwide reputation as a leader in the study of active volcanism. Due to the relatively non-explosive nature of Kīlauea's volcanic eruptions for many years, scientists have generally been able to study ongoing eruptions in proximity without being in extreme danger. Prior to May 2018, the observatory's offices were located at Uwekahuna Bluff, the highest point on the rim of Kīlauea Caldera. The summit collapse events during the 2018 eruption of Kīlauea damaged those facilities, so the observatory has since been operating from various temporary offices located in Hilo on the Island of Hawaii. History Besides the oral history of Ancient Hawaiians, several early explorers left records of observations. Rev. William Ellis kept a journal of his 1823 missionary tour, and Titus Coan documented eruptions through 1881. Scientists often debated the accuracy of these descriptions. When geologist Thomas Jaggar of the Massachusetts Institute of Technology gave a lecture in Honolulu in 1909, he was approached by businessman Lorrin A. Thurston (grandson of Asa Thurston who was on the 1823 missionary tour) about building a full-time scientific observatory at Kīlauea. The Hawaiian Volcano Research Association was formed by local businessmen for its support. George Lycurgus, who owned the Volcano House at the edge of the main caldera, proposed a site adjacent to his hotel and restaurant. In 1911 and 1912, small cabins were built on the floor of the caldera next to the main active vent of Halemaʻumaʻu, but these were hard to maintain. MIT added $25,000 in support in 1912 from the estate of Edward and Caroline Whitney to build a more permanent facility. The first instruments were housed in a cellar next to the Volcano House called the Whitney Laboratory of Seismology. Inmates from a nearby prison camp had excavated through of volcanic ash. Massive reinforced concrete walls supported a small building built on top of the structure. Professor Fusakichi Omori of Japan, now best known for his study of aftershocks, designed the original seismometers. This seismograph vault (building number 29 on a site inventory) is state historic