The eruption of Vesuvius in 79 C.E. prompted the first scientific expedition (by Pliny the Elder) to study volcanic phenomena, as well as the first written eyewitness account (by Pliny the Younger) of eruptive activity.

The new science of geology emerged in the 19^th century, focusing on the deduction of past events from current Earth exposures – “the present is the key to the past.” (Tilling)

The history of Hawaiian Volcano Observatory (HVO) begins with a geologist named Thomas A Jaggar, who witnessed the deadly aftermath of volcanic and seismic activity during a decade-long exploration of volcanoes around the world.

The devastation he observed, particularly that caused by the 1902 eruption of Mount Pelée on the Caribbean Island of Martinique, led Jaggar to his vision and life-long work to “protect life and property on the basis of sound scientific achievement” by establishing Earth observatories throughout the world.  (USGS)

At that time, there was only one volcano observatory in the world – at Vesuvius, established in 1841 under King Fernando II to keep an eye on the active volcanoes near Naples. Jaggar thought America needed one.  (Apple)

In early 1911, Jaggar convinced Frank A Perret, a world-famous American volcanologist he had met on Vesuvius Volcano in Italy, to travel to Hawai‘i to begin the observations of Kīlauea’s volcanic activity.

From July to October 1911, Perret conducted experiments and documented the lava lake activity within Kïlauea’s Halema‘uma‘u Crater, paving the way for Jaggar to pursue his life’s goal of using multiple scientific approaches and all available tools for the observation and measurement of volcanoes and earthquakes.

In 1911, the first scientific laboratory at Kilauea consisted of a crude wooden shack constructed on the edge of Halema‘uma‘u that was called the Technology Station. The next year saw the construction by Jaggar of the Hawaiian Volcano Observatory. 

(Subsequently, the Technology Station was relocated and improved, and a structure called the “Instrument Shelter” (extending over the rim of Halemaʻumaʻu) was built with a wall open to the crater for a wide-angle view.)

Jaggar arrived at the Volcano House hotel on January 17, 1912; the Hawaiian Volcano Observatory was established by Jaggar, and for the first seven years of its existence it operated on funds provided by the Massachusetts Institute of Technology (MIT) from its Whitney Fund for research in geophysics and by the Hawaiian Volcano Research Association.

The latter is a group of persons, largely residents of Hawaii and principally businessmen, who are actively interested in the study of volcanoes.

“There is no place on the globe so favorable for systematic study of volcanology and the relations of local earthquakes to volcanoes as in Hawaii … where the earth’s primitive processes are at work making new land and adding new gases to the atmosphere.”  (Thomas A Jaggar, 1916)

Upon his arrival, he established a routine of daily observations of the ongoing eruption in Halemaʻumaʻu Crater. “Keep and publish careful records, invite the whole world of science to co-operate, and interest the business man.” (Jaggar, 1913)

He developed uniform note pads with detachable sheets for use by all employees and insisted that anyone from the observatory who visited the crater take notes of their observations.

In 1919 the administration of the Volcano Observatory was taken over by the United States Weather Bureau, which was then charged by Congress with the responsibility for earthquake investigations in the United States.

In 1924 the Observatory passed to the US Geological Survey, in 1935 to the National Park Service, and in 1948 back to the Geological Survey. It is currently a part of the Geological Survey’s volcano investigation program.

The original location of the Volcano Observatory was the site now occupied by the Volcano House. The Whitney Laboratory of Seismology is a concrete vault beneath the western end of the Volcano House. (The vault is under the grassy mound on the Halema‘uma‘u side of the hotel.)

When the present Volcano House was built in 1941, the Observatory was transferred to what is now the Park Museum and Administration Building, and in 1948 to a building on the western rim of Kilauea caldera at Uekahuna. Dr Jaggar continued as Director of the Observatory until his retirement in 1940.

Since 1912, Kilauea and Mauna Loa volcanoes have been under constant close observation by members of the Observatory staff. The purpose of the studies by the Volcano Observatory have two general aspects, the humanitarian or practical aspect and the strictly scientific.

The two are difficult to separate, because a phase that belongs to pure science today may become of great practical importance within a few years.

In general, the scientific aspects of the Observatory program are directed toward an understanding of the subsurface structure of the volcanoes, the nature and properties of the magma, how the volcano behaves, and why.

The humanitarian aspects include prediction of eruptions and the course of lava flows once the eruption has started and issuing warnings of danger from lava flows.

An example of one phase of the Observatory’s program that is of purely scientific importance is the investigation of the volcanic gases and their relation to the magma and effects on surrounding rocks.

The Observatory also makes visual observations of the volcanic eruptions, collects gas and lava samples, determines temperatures of liquid and solidifying lava and of the gases, measures the width of many cracks about Kilauea caldera as they open and close, operate tilt-meters and a series of magnetometer stations on Kilauea and the slopes of Mauna Loa, and a net of seismograph stations.

Very early in the history of the Observatory it was found that the ground surface on the slopes of the volcano was constantly tilting in one direction or another, and it was soon shown that this tilting correlated with activity of the volcanoes.

Preceding eruption the whole volcano swells up, as though it were being inflated like a big balloon. This produces an outward tilting on its sides. Following the eruption the volcano contracts and the slopes tilt inward.

This swelling and tilting can be measured by leveling, of the sort done in ordinary surveying. By leveling from sea-level at Hilo, it was found that during the interval from 1912 to 1921 a bench mark near the Observatory apparently rose about 3 feet.

Releveling in 1927, after the great collapse and steam explosions of 1924, showed that the same bench mark had lowered 3.5 feet, while a bench mark near the rim of Halema‘uma‘u had gone down about 13 feet.

Ordinarily, however, the tilting of the ground surface is measured not by leveling, but by sensitive pendulums known as tilt-meters. Such tilt-meters in operation by the Observatory are capable of indicating an angle of tilt of less than one-tenth of a second.  (A tilt of one-tenth of a second would displace the top of a pole ten miles high about a quarter of an inch).

Volcanic tilt of many seconds of arc has been measured on the tilt-meters. Strong outward tilting of the ground surface, especially when combined with numerous earthquakes, is a good indication of magma rising in the volcano and the possibility of impending eruption.

Magnetometer measurements by the Volcano Observatory were started early in 1950. A magnetometer is an instrument used to measure the strength of the earth’s magnetic attraction at any given locality.  The strength of the earth magnetism depends on several factors.

One cause of decrease in the strength of magnetism is rise in temperature of the underlying rock. As magma rises beneath the surface the surrounding rocks are heated up, and their magnetism decreases.  Detecting this aids in prediction of eruptions.

A seismograph is a device to record earthquakes. The essential portion of most seismographs is a pendulum. Because of its inertia, during earthquakes a freely suspended pendulum tends to stand still while the earth moves under it.

The effect is nearly the same at it would be if the earth were still and the pendulum vibrating. This apparent movement of the pendulum is recorded in various ways – by direct mechanical means, by directing a beam of light onto photographic paper, or electrically.

So long as the earth is quiet the writing point draws a straight line on the smoked paper, but when an earthquake occurs the pendulum vibrates with respect to the ground and the recording drum, and the line drawn on the smoked paper is wiggly.

By identifying the times of arrival of the different types of vibration, and measuring the interval of time between them, the distance from the station at which the earthquake originated can be calculated. Then, by using the distances of origin from several stations, the epicenter and depth of origin of the earthquake can be located.

Any marked increase in the number of earthquakes indicates a restlessness of the volcano in which the earthquakes originate, and the location of the earthquake indicates what portion of the volcano is involved. Commonly an eruption of either volcano is preceded by a series of earthquakes.

These earthquakes begin at a depth of 25 to 30 miles, but as the series progresses the places of origin get gradually closer to the surface and often shift laterally, finally centering at a place close to the site of the coming eruption. Thus, earthquakes are of great value to the volcanologist in predicting coming activity.  (Information is copied from NPS, Nature Notes May 1951)

During the past century, HVO has been at the forefront of developing and applying the modern techniques and instruments now used in volcano monitoring, including volcanic-gas monitors, satellite-based deformation measurements, networks of remote cameras recording eruptive activity, and seismic networks such as the Hawai‘i Regional Seismic Network.

The first seismic network in the USGS was installed on Kīlauea in the 1950s, and earthquake monitoring has been important both as a tool for volcano monitoring and for assessing seismic hazards in the State of Hawaii. HVO has been a training ground for volcanologists from the United States and around the world.

By December 1915, with Jaggar having worked in Hawai‘i for three years, the Research Association and MIT sent him to Washington DC to appeal to Congress to take over HVO as a government institution.  In addition, the governor of Hawai‘i and the Honolulu Chamber of Commerce asked him to continue to push for the establishment of a national park. (Moniz Namakura)

(On August 1, 1916, President Woodrow Wilson signed the bill establishing Hawaii National Park as the nation’s 13^th national park.  It included lands surrounding Kīlauea and Mauna Loa volcanoes on Hawaiʻi Island, and Haleakalā on the island of Maui.  In July 1961, Hawai‘i National Park was split into two distinct areas:  Haleakalā National Park and Hawai‘i Volcanoes National Park.)

The US Geological Survey (USGS) has operated HVO continuously since 1947.  Before then, HVO was under the administration of various Federal agencies – the US Weather Bureau, at the time part of the Department of Agriculture, from 1919 to 1924; the USGS, which first managed HVO from 1924 to 1935; and the National Park Service from 1935 to 1947.

It currently operates under the direction of the USGS Volcano Science Center, which now supports five volcano observatories covering six US areas – Hawaiʻi (HVO), Alaska and the Northern Mariana Islands (Alaska Volcano Observatory), Washington and Oregon (Cascades Volcano Observatory), California (California Volcano Observatory), and the Yellowstone region (Yellowstone Volcano Observatory).

For much of its history, HVO was perched dramatically on the rim of Kīlauea Volcano’s summit caldera inside Hawai‘i Volcanoes National Park. That ended in 2018, when – amid ash explosions and violent earthquakes accompanying onset of partial summit collapse – HVO relocated to the town of Hilo, 30 miles distant.

Due to substantial damage to the building, new facilities in Hilo and inside the national park are planned. In the meantime, most of HVO remains in Hilo in the historic Ironworks Building on Kamehameha Avenue. HVO continues to use some facilities inside the national park and a warehouse in Kea‘au.  (USGS)

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