History of Mauna Loa in Timeline

Mauna Loa, situated on the Island of Hawaii, is one of the Earth's most massive volcanoes. Although previously considered the largest, it is surpassed in size by Tamu Massif. This shield volcano features gentle slopes and an estimated volume of 18,000 cubic miles. Despite its immense size, its peak sits lower than its neighbor, Mauna Kea. Mauna Loa is known for its non-explosive eruptions due to its fluid, silica-poor lava.

1903: Multiple Eruptions

Mauna Loa erupted twice in 1903, indicating a period of heightened volcanic activity.

1907: Mauna Loa Eruption

Continuing its active phase, Mauna Loa erupted in 1907, adding to its history of frequent eruptions.

1912: Monitoring Begins

Recognizing the potential hazards of Mauna Loa, the Hawaiian Volcano Observatory began intensively monitoring the volcano in 1912.

1912: Establishment of the Hawaiian Volcano Observatory

The Hawaiian Volcano Observatory (HVO) was established in 1912 on Kilauea. Its primary mission is to monitor and study Hawaiian volcanoes.

1914: Mauna Loa Eruption

Mauna Loa erupted in 1914, marking another event in its series of eruptions during the early 20th century.

1914: Attempted Summit Expedition to Mauna Loa by Thomas A. Jaggar

Thomas A. Jaggar, founder of the HVO, made an unsuccessful attempt to reach Mauna Loa's summit to observe its eruption in 1914 due to the difficult journey.

1915: Construction of a Route to Mauna Loa's Summit

In 1915, with support from Lorrin A. Thurston and the US Army, a route to Mauna Loa's summit was completed, simplifying access for scientific study and public use.

1916: Mauna Loa Eruption

Adding to its active period, Mauna Loa erupted once again in 1916, showcasing its consistent volcanic activity.

1916: Mokuʻāweoweo Becomes Part of Hawaii Volcanoes National Park

In 1916, Mokuʻāweoweo was included in the Hawaii Volcanoes National Park, leading to the construction of a new trail from the park headquarters at Kilauea.

1919: Partially Subaerial Eruption

Mauna Loa experienced a partially subaerial eruption in 1919, characterized by both underwater and above-ground activity.

1924: Volcanic Fatality

A rare fatality from volcanic activity in Hawai'i occurred in 1924 at Kilauea, underscoring the potential dangers despite the typically slow-moving lava flows.

1926: Village Destruction

A notable eruption of Mauna Loa occurred in 1926 when lava flows destroyed villages, highlighting the potential danger of the volcano.

1926: Village Overrun by Lava

The 1926 eruption of Mauna Loa resulted in the destruction of the village of Ho'ōpūloa Makai, highlighting the destructive power of lava flows, even if they are generally slow-moving.

1933: Mauna Loa Eruption

Mauna Loa erupted again in 1933, continuing its trend of frequent eruptions during this era.

1934: Summit Shelter Construction

A summit shelter was built in 1934 using stones from the Wilkes' camp site and mortar.

1934: Volcanic Activity Shift

An interesting observation noted that when Kilauea became dormant in 1934, Mauna Loa became more active. This suggests a possible interaction between the two volcanoes.

1935: Hilo Threatened by Lava Flows

The 1935 eruption of Mauna Loa posed a serious threat to Hilo when lava flows started heading toward the city, leading to intervention efforts to divert the flows.

January 2, 1936: Lava Flow Stops

After a bombing operation aimed at diverting lava flows from Mauna Loa's 1935 eruption, the lava stopped flowing on January 2, 1936. However, the effectiveness of the bombing remains a subject of debate.

1940: Summit-Bound Eruption

In contrast to the more impactful 1935 eruption, a summit-bound event in 1940 was relatively less consequential, as the lava flows were confined to the summit area.

1942: WWII Eruption and Bombing

Mauna Loa's 1942 eruption coincided with World War II. Concerns about the eruption's glow being used by the Japanese led to a news blackout and bombing attempts to divert lava flows, showcasing the intersection of natural events and wartime anxieties.

1949: Mauna Loa Eruption

Mauna Loa erupted in 1949, a precursor to the more significant eruption that would follow in 1950.

1950: Rapid Lava Flow

Mauna Loa's 1950 eruption demonstrated the potential for rapid lava flow, reaching sea level in just four hours. This event challenged the perception that Hawaiian eruptions always involve slow-moving lava.

1950: Largest Rift Event

Mauna Loa's 1950 eruption holds the record for the largest rift event in its recorded history, emitting a massive amount of lava and reaching the ocean in a remarkably short time. This event significantly impacted the landscape and destroyed the village of Ho'okena-mauka.

1950: Village Destruction

Similar to the 1926 eruption, Mauna Loa's eruption in 1950 resulted in the destruction of villages. These events underscore the destructive power of the volcano.

1952: Volcanic Activity Shift

Reinforcing the observed trend, when Mauna Loa became quiet in 1952, Kilauea became more active, further hinting at a link between the activities of the two volcanoes.

February 20, 1962: Lowest Temperature Recorded on Mauna Loa

On February 20, 1962, the lowest temperature ever recorded on Mauna Loa was documented, plunging to a frigid 18°F (-8°C).

July 24, 1974: Wilkes Expedition Camp Site Listed on National Register of Historic Places

On July 24, 1974, the camp site of the Wilkes expedition was officially recognized for its historical importance and added to the National Register of Historic Places.

1974: Volcanic Activity Shift

Continuing the pattern, Mauna Loa's quiet period from 1952 to 1974 coincided with heightened activity at Kilauea, solidifying the observed correlation between the two volcanoes.

1974: Seismic Unrest Precedes Mauna Loa Eruption

Starting in 1974, Mauna Loa showed signs of increased seismic activity, providing a warning signal for its eruption in the following year.

July 1975: Mauna Loa Eruption

Mauna Loa erupted in July 1975, an event that was anticipated due to over a year of seismic unrest, leading to public warnings from late 1974.

1975: Brief Summit Eruption

After the substantial 1950 eruption, Mauna Loa experienced a long period of dormancy, punctuated only by a small, single-day summit eruption in 1975.

1975: Magma Chamber Model

Geophysical models of Mauna Loa's magma chamber were created using data from the 1975 eruption. These models provide insights into the volcano's internal structure.

1975: Hilina Slump

In 1975, the Hilina Slump on Mauna Loa shifted several meters, causing a 7.2 magnitude earthquake and a tsunami that reached heights of 14 meters. The tsunami tragically resulted in the loss of two lives at Halape.

1975: Ground Deformation Measurement

In the year leading up to the 1975 eruption of Mauna Loa, a survey line across the caldera indicated a 76 mm increase in width, highlighting the significance of ground deformation monitoring.

1983: Volcanologists Predict Eruption

By 1983, volcanologists had observed significant seismic activity on Mauna Loa, accurately predicting an eruption within two years.

1984: Simultaneous Eruption

Contradicting the typical pattern, Mauna Loa erupted in 1984 during an ongoing eruption at Kilauea, demonstrating that the two volcanoes don't always operate in a strictly inverse manner.

1984: Magma Accumulation Begins

Following the 1984 eruption, magma began accumulating beneath Mauna Loa, a natural process as the volcano recharged. This accumulation continued until the next eruption in 2022.

1984: Hilo Threatened Again

Hilo faced another close call during the 1984 eruption of Mauna Loa when lava flows came close to the city. This event served as a reminder of the city's location on lava flows from a previous eruption and the inherent risks associated with its position.

1984: Previous Mauna Loa Eruption

Prior to the 2022 eruption, Mauna Loa's most recent eruption occurred in 1984.

1984: Magma Chamber Model

Refining previous understanding, the 1984 eruption of Mauna Loa contributed to improved geophysical models of the volcano's magma chamber, enhancing our knowledge of its internal workings.

1984: Ground Deformation Precedes Eruption

Similar to the events preceding the 1975 eruption, a comparable increase in ground deformation was observed in the year before Mauna Loa's 1984 eruption.

1984: Near Miss for Hilo

The 1984 eruption of Mauna Loa saw lava flows come dangerously close to Hilo, highlighting the city's vulnerability to the volcano's activity. Fortunately, natural levees diverted the flows, preventing a potential disaster.

1985: Longest Quiet Period Begins

Following the 1984 eruption, Mauna Loa entered its most extended quiet period in recorded history, lasting until 2022. This dormancy, while lengthy, was not unexpected, as the volcano was recharging after the previous eruption.

September 26, 1990: Highest Temperature Recorded on Mauna Loa

On September 26, 1990, the highest temperature ever recorded on Mauna Loa was measured, reaching 78°F (26°C).

October 2006: Establishment of the Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA)

In October 2006, the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) established the Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) on Mauna Loa to study cosmic microwave background radiation.

2019: Increased Unrest Observed

Starting in 2019, scientists observed an uptick in unrest at Mauna Loa, signaling a potential shift in the volcano's activity and hinting at the possibility of a future eruption.

February 2021: Elevated Unrest

In February 2021, the U.S. Geological Survey reported heightened signs of unrest at Mauna Loa since 2019, including increased inflation at the summit, indicating the potential for future eruptions.

November 27, 2022: Mauna Loa Eruption Begins

Mauna Loa's most recent eruption commenced on November 27, 2022. This marked the volcano's first eruption in 38 years since 1984.

December 13, 2022: Mauna Loa Eruption Ends

Mauna Loa's eruption, which began on November 27, 2022, ended on December 13, 2022.

2022: Longest Quiet Period Ends

Mauna Loa's long period of quiet, which began in 1985, finally ended in 2022 with the volcano's most recent eruption, marking the end of its longest recorded dormancy.

2022: Simultaneous Eruption

Similar to the 1984 event, the 2022 eruption of Mauna Loa occurred during an ongoing eruption at Kilauea, further illustrating that the two volcanoes can erupt simultaneously.