Hawaii Volcanoes National Park | Page 2

January 6, 2024 by Peter T Young Leave a Comment

Buffalo Soldiers Trail

In early 1911, geologist named Thomas A 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.

When Jaggar came to the Islands, he joined the efforts of George Lycurgus (operator of the Volcano House) and newspaperman Lorrin Andrews Thurston who were working to have the Mauna Loa and Kilauea Volcanoes area made into a National Park.

Jaggar had tried to lead several expeditions to the top of Mauna Loa in 1914 but was unsuccessful due to the elevation (13,678 feet) and the harsh conditions: rough lava, violent winds, noxious fumes, shifting weather, extreme temperatures and a lack of shelter, water and food. (Takara)

In September 1915, Jaggar, Thurston and a US Army representative conducted a survey to determine a route for a trail up Mauna Loa.

The following month, a local paper noted, “Soldiers Building Mountain Trail. Negro soldiers of the Twenty-fifth Infantry to the number of 150 are at work constructing a trail from near the Volcano House to the summit of Mauna Loa.”

“It is estimated that three or four weeks will be devoted to this work. The soldiers are doing the work as a part of their vacation exercises.” (Maui News, October 29, 1915)

Immediately after the Civil War and the abolition of slavery, many African Americans found themselves newly freed from bondage. In 1866, congress created four military regiments made up of Black troops, the 9th and 10th Cavalry and the 24th and 25th Infantry – they were known colloquially as the Buffalo Soldiers. (NPS)

“Although Native Americans bestowed the name upon the troopers, there are differing accounts as to the reason. One account suggests the name was acquired during the 1871 campaign against the Comanches, when Indians referred to the cavalrymen as “Buffalo Soldiers” because of their rugged and tireless marching.”

“Other accounts state that Native Americans bestowed the nickname on the black troopers because they believed the hair of the black cavalrymen resembled the hair of the buffalo.”

“Another suggests that the name was given because of the buffalo-hide coats worn by the soldiers in cold weather. The troopers took the nickname as a sign of respect from Native Americans, who held great reverence for the buffalo, and eventually the Tenth Cavalry adopted the buffalo as part of its regimental crest.” (Plante)

“The generous cooperation of the United States Army has made the trail to the top of Mauna Loa and the rest houses at the top and midway thereto a certainty.” (Hawaiian Gazette, Sep 24, 1915)

“The overpowering feature of the landscape, however, is the immediate foreground to the north and east. The trail up to Red Crater is through ordinary and rather monotonous lava flows; but from the top of the hill there literally bursts into view a scene of most violent volcanic activity that I have seen anywhere.”

“It is similar to the interior of Haleakala crater; and the top of Hualalai, but while those are old and faded, this is fiery red and inky black.” (Hawaiian Gazette, Nov 11, 1915)

“During the past summer [in 1915] the promotion committee and Research Association formulated and presented its plan to the authorities of the County of Hawaii and the newly created Hawaii Publicity Committee …”

“… proposing that these two organizations with the assistance of private subscriptions should furnish the money necessary for the material involved, the work to be done by the county prisoners.”

“The county authorities and the publicity committee each agreed to contribute $500 toward the enterprise. Then the Governor came in with a contribution of $500 from the contingent fund and private subscriptions have been received in excess of $1000.”

“No decision had been arrived at concerning the availability of the county prisoners, however.” (Hawaiian Gazette, Sep 24, 1915) (The practice in Hawai‘i and elsewhere was to use prison labor for public works projects, including road building.)

(Later Territorial law stated, “All prisoners sentenced to imprisonment at hard labor shall be constantly employed for the public benefit, on public roads or other public works or other wise, as the high sheriff, with the approval and subject to the control of the board of prison directors, may deem best.”)

Then the military offered aid in the form of a “tentative proposition that, if transportation was furnished from Honolulu to Hilo and return, Company E of the Twenty-fifth Infantry, consisting of between 140 and 150 men would volunteer to go to Volcano, and do the work of building the trail and erecting the rest houses without further expense to the promoters or enterprise.” (Hawaiian Gazette, Sep 24, 1915)

Building the Buffalo Soldiers Trail (now called Mauna Loa Trail) from the 4,000-ft. summit of Kīlauea to the 13,677-ft. summit of Mauna Loa was no easy task. (NPS)

“The soldiers are constructing a trial three feet wide across the a-a, crushing it down with twelve pound hammers, filling in hollow, cutting down ridges and putting on a finish of fine a-a and earth, quarried along the line or parked in gunny sacks, carried on the men’s backs – in some places being carried as far as a quarter of a mile.”

“The Mauna Loa trail and rest house project is making steady and substantial progress. It must be remembered that it is through a section of territory never before inspected, much less traveled over, except the lower portion thereof, and that only by a few surveyors, cattle men and catchers of wild goats.”

“No one wants to run away with the idea that the job which the men of Company E of the Twenty-fifth Infantry have volunteered to do is all picnic. They are having a picnic all right; but incidentally they are doing a lot of good hard work in a pure pro bono publico spirit.” (Hawaiian Gazette, Nov 11, 1915)

The Buffalo Soldiers built the 18-mile trail to the summit of Mauna Loa. They also built the ten-man Red Hill Cabin and a twelve-horse stable, so scientists could spend extended periods of time studying the volcano.

“[D]uring the period of 1915 to 1921, the trail was managed and maintained by a loose consortium consisting of Hawaii Volcano Research Association, Lorrin Thurston, Hilo businessmen, and Thomas Jaggar, then it was managed by the National Park Service.” (Tuggle)

Between 1930 and 1932, the National Park carried out major improvements and realignments of the Mauna Loa Trail to fall completely within the park boundary. Over the past century, the evolving needs of the National Park and changes in available

technology have resulted in ongoing modifications to the physical footprint of the trail.

The uppermost portion of the original trail footprint has been nearly obliterated since the 1970s by a series of large lava flows in 1975, 1984, and 1985. (Tuggle) (The inspiration and sources to information here came primarily from a study by Myra Tomonari-Tuggle.)

November 14, 2023 by Peter T Young Leave a Comment

Kilauea Iki Eruption – 1959

Volcanologists knew something was coming.

Between November 1957 and February 1959 measurements from newly installed sensitive tiltmeter bases around the summit indicated that the whole caldera region was tilting outward, apparently because magma was welling up from the mantle and accumulating in the reservoir several miles beneath the caldera.

Between August 14 and 19, 1959, a swarm of deep earthquakes was recorded on the seismographs at the Hawaiian Volcano Observatory. The earthquakes were located about 35-miles below the volcano.

By October, tilt surveys of the caldera, using the new water-tube tiltmeter network, indicated that the summit reservoir of Kīlauea was beginning to inflate with new magma. Scientists later concluded that magma began its upward journey during the August swarm.

Another series of earthquakes – shallow tiny events beneath the caldera – began in mid-September near Halema‘uma‘u Crater. By November 1, more than 1,000 tiny earthquakes were being recorded per day.

Scientists conducted another caldera tilt survey during the second week of November and discovered it was swelling at least three times faster than during the previous months. Magma was moving into the summit reservoir at a high rate.

During the afternoon of November 14, earthquakes beneath the caldera suddenly increased about tenfold in both number and intensity. For five hours, the entire Kīlauea summit region shook as seismic tremor signaled magma was forcing its way from the summit reservoir toward the surface.

An erupting fissure of small lava fountains broke through the south wall of Kīlauea Iki Crater at 8:08 p.m. In the first 24 hours, activity decreased and then eventually ceased at the outermost fissure vents. By nightfall on November 15, only a single vent on the west side of the fissure remained active.

Over the next five days, lava fountain heights fluctuated between about 650 and 980-feet, with a maximum fountain height of 1,247-feet.

A brand new cinder cone called Puʻupuaʻi (translates to “gushing hill”) was formed. As cinder and spatter rapidly accumulated to form Puʻupua‘i, slabs of congealed spatter occasionally broke loose and slid down the cone into the churning lava lake.

The 1959 summit eruption occurred in Kilauea Iki, a collapse crater adjacent to the main summit caldera of Kilauea. There were 17 eruptive ‘episodes’ (or phase) of the eruption which ranged in duration from 1 week to 1¾-hours..

On December 17, episode 15 produced lava fountains that were approximately 1,900-feet high, the highest recorded in Hawaii during the 20th century.

That’s about three times the size of the Washington Monument. That’s also 124 feet higher than the tallest building in the US now: One World Trade Center. (CNN)

Downwind from high lava fountains, forests suffered tremendous damage. Trees were stripped of leaves and branches – or completely buried – by falling cinder. You can now walk through this area of the National Park; it’s called ‘Devastation Trail.’

A few ōhi‘a trees, dead and bleached, poke up through the pumice and very gradually some ōhi‘a, ōhelo and ferns are beginning to recolonize the dead zone (unfortunately, some blackberry, too.)

Here is a video of the eruption (unfortunately, there is no sound, the sound of an eruption is as impressive as the visual):

The lava lake attained its greatest depth (414 feet) and volume (58 million cubic yards) at the end of the eighth phase on December 11, 1959. The eruption ended December 20, 1959.

When we were kids, living on Kāne‘ohe Bay on O‘ahu, whenever the eruption happened we’d go to the Big Island to see it, including the 1959 eruption of Kīlauea Iki.

April 11, 2023 by Peter T Young Leave a Comment

Whose Footprints Are These?

Geologic evidence suggests that the modern caldera of Kīlauea formed shortly before 1500 AD. Repeated small collapses may have affected parts of the caldera floor, possibly as late as 1790. For over 300-400 years, the caldera was below the water table.

Kilauea can be an explosive volcano; several phreatic eruptions have occurred in the past 1,200 years. (Phreatic eruptions, also called phreatic explosions, occur when magma heats ground or surface water.)

The extreme temperature of the magma (from 932 to 2,138 °F) causes near-instantaneous evaporation to steam, resulting in an explosion of steam, water, ash and rock – the 1980 eruption of Mount St. Helens was a phreatic eruption.

The 1924 eruption at Halemaʻumaʻu documents and illustrates the explosive nature of Kilauea. However, the 1924 explosions were small by geologic standards and by the standards of some past Kilauea explosions.

The hazards of larger explosions, such as those that took place multiple times between about AD 1500 and 1790, are far worse than those associated with the 1924 series. (USGS)

There were explosions in 1790, the most lethal known eruption of any volcano in the present United States. The 1790 explosions, however, simply culminated (or at least occurred near the end of) a 300-year period of frequent explosions, some quite powerful. (USGS)

Keonehelelei is the name given by Hawaiians to the explosive eruption of Kilauea in 1790. It is probably so named “the falling sands” because the eruption involved an explosion of hot gas, ash and sand that rained down across the Kaʻu Desert. The character of the eruption was likely distinct enough to warrant a special name. (Moniz-Nakamura)

At the time, Kaʻū Chief Keōuakūʻahuʻula (Keōua) was the only remaining rival of Kamehameha the Great for control of the Island of Hawaiʻi; Keōua ruled half of Hāmākua and all of Puna and Kaʻū Districts. They were passing through the Kilauea area at the time of the eruption. The 1790 explosion led to the death of one-third of the warrior party of Keōua. (Moniz-Nakamura)

Camped in Hilo, Keōua learned of an invasion of his home district of Kaʻū by warriors of Kamehameha. To reach Kaʻū from Hilo, Keōua had a choice of two routes one was the usually traveled coastal route, at sea level, but it was longer, hot, shadeless and without potable water for long distances. (NPS)

The other route was shorter, but passed over the summit and through the lee of Kilauea volcano, an area sacred to, and the home of, the Hawaiian volcano goddess Pele. Keōua chose the volcano route, perhaps because it was shorter and quicker, with water available frequently. (NPS)

In 1919, Ruy Finch, a geologist at the Hawaiian Volcano Observatory discovered human footprints fossilized in the Kaʻū desert ash. Soon, this area of the desert became known as “Footprints.”

Barefoot walkers left thousands of footprints in wet volcanic ash within a few miles southwest of Kīlauea’s summit.

Many historians and Hawaiians believe the footprints were made by Keōua and his warriors. Keōua was known to be in the area at the time, and previous thought suggested this part of the desert did not have pre-contact use, so it was narrowed down to them.

Scientists later investigated – one approach was to look deeper at the evidence.

Forensic studies indicate that the length of a human foot is about 15% of an individual’s height. A man’s foot may be slightly more that 15%, a woman’s slightly less, but it is possible to estimate the height to a couple of inches. (USGS)

They measured 405-footprints to determine how tall the walkers were. The average calculated height is only 4-feet 11-inches, and few footprints were made by people 5-feet 9-inches or more tall. Early Europeans described Hawaiian warriors as tall; one missionary estimated an average height of 5-feet 10-inches. Many now believe that most of the footprints were made by women and children, not by men, much less warriors. (USGS)

Meanwhile, Keōua’s party was camped on the upwind side of Kīlauea’s summit – perhaps on Steaming Flat – waiting for Pele’s anger to subside. They saw the sky clear after the ash eruption and began walking southwestward between today’s Volcano Observatory and Nāmakanipaio. (USGS)

Suddenly, the most powerful part of the eruption began, developing a high column and sending surges at hurricane velocities across the path of the doomed group. Later, survivors and rescuers made no footprints in the once wet ash, which had dried. (USGS)

Then, archaeologists looked for other evidence to help identify who the footprints may have belonged to. Contrary to general thought that the area was not used by the Hawaiians, archaeological investigations discovered structures, trails and historic artifacts in the area. (Moniz-Nakamura)

Most of the features were along the edge of the Keʻāmoku lava flow. Several of the trails converge south of the flow, suggesting a major transportation network. The structures are likely temporary, used as people were traversing through the desert on their way to/from Kaʻū and Hilo. (Moniz-Nakamura)

The sheer number of temporary shelters along the Keʻāmoku flow, as well as the trail systems and quarry sites, strongly suggest that this area was frequently used by Hawaiians travelling to and through the area – before and after the 1790 eruption. (Moniz-Nakamura)

If the footprints aren’t Keōua’s warriors, then how did one-third of his warriors die?

Several suggestions have been made: suffocation due to ash; lava, stones, ash and other volcanic material; or strong winds produced by the eruption, asphyxiation and burning killed them. (Moniz-Nakamura)

A more recent suggestion is that a “hot base surge, composed primarily of superheated steam … (traveling at) hurricane velocity” was the cause of death. The wind velocity prevented the people from running away; they probably huddled together, then “hot gases seared their lungs.” (Moniz-Nakamura)

Some now suggest that, if these observations and ideas are correct, the footprints were made in 1790, but not by members of Keōua’s group. (USGS)

A reconstruction of events suggests that wet ash, containing small pellets, fell early in the eruption, blown southwestward into areas where family groups, mainly women and children, were chipping glass from old pāhoehoe. They probably sought shelter while the ash was falling. Once the air cleared, they slogged across the muddy ash, leaving footprints in the 1-inch thick deposit. (USGS)

On August 1, 1916, President Woodrow Wilson signed the country’s 13th national park into existence – Hawaiʻi National Park. At first, the park consisted of only the summits of Kilauea and Mauna Loa on Hawaiʻi and Haleakalā on Maui.

Eventually, Kilauea Caldera was added to the park, followed by the forests of Mauna Loa, the Kaʻū Desert, the rain forest of Olaʻa and the Kalapana archaeological area of the Puna/Kaʻū Historic District.

In 1961, Hawaiʻi National Park’s units were separated and re-designated as Haleakalā National Park and Hawaii Volcanoes National Park.) (Lots of good information here is from USGS, NPS and Jade Moniz-Nakamura.)

February 26, 2023 by Peter T Young Leave a Comment

Kenichi Maehara

“After 20 years of service as clerk in the Hilo post office, K Maehara will retire to private life at the end of this month. He is leaving the postal service on account of impaired eyesight and will devote his entire attention to the management of the Camera Craft Shop at Kamehameha Ave.” (Star Bulleting, May 21,1921)

Born in Japan on April 2, 1880, Kenichi (also Kenzo) Maehara was a prominent Hawaiian photographer who owned the Camera Craft Shop in Hilo. He also held the photography concession in the Hawai‘i National Park (now known as the Hawai‘i Volcanoes National Park.

He built and operated the Volcano Photo Studio adjacent to the on-site hotel, the Volcano House, near what is today’s Kīlauea Visitor Center. (He also operated an “up-to-date portrait studio” in the Osorio building in Hilo.

Maehara specialized in developing, printing, enlarging, coloring, and framing pictures, photographs, and lantern slides of park and island scenes. He also sold postcards, some from photographs taken by others.

Maehara came to Hawai‘i from Hiroshima, Japan in 1896 and over his 30-year career grew to become a renowned and respected local businessman whose photos of volcanic eruptions were published and distributed around the world.

He photographed the Kilauea 1924 eruption; then, Mauna Loa (“Long Mountain”) began erupting at 6:20 pm on November 21, 1935.

Lava flows from Mauna Loa were generally fast-moving and voluminous. Lava moved relentlessly at a rate of five-miles each day; it pooled up between Mauna Kea and Mauna Loa at about where the Saddle Road is situated.

The ponded lava eventually began to follow the lay of the land, a natural drainage … Then, things “got interesting.” Lava was heading directly toward Hilo. (USGS)

Dr. Thomas A Jaggar Jr, the government volcanologist, estimated that the flow would reach Hilo by January 9, 1936. He suggested using dynamite to collapse lava tubes near the source of the flow in order to stop or divert it.

Explosives were first suggested as a means to divert lava flows threatening Hilo during the eruption of 1881. However, Jaggar’s plan of mule teams hiking the explosives up the mountain would take far too long – the lava flows were moving a mile a day.

It was suggested to use US Army Air Corps bombers to precisely deliver explosives. Jaggar agreed, and the call was made. The US Army Air Corps approved, and the mission and plans to strategically bomb Mauna Loa were set into motion.

Maehara took photos of the lava bombing on request from the director of the Hawaiian Volcano Observatory. Ironically the same photos that were commissioned by the US government.

As it turned out, after the Japanese military attack on Pearl Harbor on December 7, 1941, Maehara was arrested and detained under suspicion of disloyalty to the United States. Evidence used against him included photos he took of the 1935 US military bombing of a Mauna Loa lava flow.

Because of this and his participation in the local Japanese community, Maehara was declared a security threat. Army intelligence officers discovered a significant amount of cash at his premises as well as a large number of pornographic pictures, which, apparently, he had sold regularly to visiting soldiers. (Chapman)

Maehara was sent to detention facilities in Honolulu, and he was later transferred to an internment camp in the state of New Mexico.

Shortly thereafter, the newspaper reported, “The permit of K Maehara to operate a photographic concession in the Kilauea section was cancelled December 31 and will not be renewed. Mr Maehara, a Japanese alien, is interned by the authorities.” (Star Bulletin, August 12, 1942)

With the photography concession canceled on December 31, 1941, the Park’s chief clerk deposited the former concessioner’s cash; NPS employees removed his equipment to a vacant park residence, and boarded up the concession building for the time being. (Chapman)

In 1943, while he was still interned, Maehara’s Volcano Photo Studio was demolished. He would never return to the national park in an official capacity.

He returned to the Islands. In 1950, Kenichi and his wife Matsue Maehara changed their names to Yokoyama (Honolulu Advertiser Sep 25, 1950) Daughter Masako Yokoyama received her PhD from Yale in 1949; she married Floyd G Lounsbury and joined her husband teaching at Yale. (Lots here is from NPS.)

January 15, 2023 by Peter T Young Leave a Comment

Hawaiian Volcano Observatory

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.

(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)