Earthquakes in Hawaii
At around 10:45am today, staff and visitors at Pu’ukohola Heiau National Historic Site were startled for a moment when a 4.4 earthquake gave the visitor center a good shake (For details on this quake, see: Earthquake Summary). Although there was no apparent damage, this small earthquake was a good reminder that Hawaii is very much seismically alive. In light of this, we’d thought we’d share the following article about earthquakes in Hawaii.
Earthquakes in Hawaii
Earthquakes in Hawai`i are closely linked to volcanism. They are an important part of the island-building processes that have shaped the Island of Hawai`i and the other Hawaiian Islands. Thousands of earthquakes occur every year beneath the Island of Hawai`i.
Eruptions and magma movement within the presently active volcanoes (Kilauea, Mauna Loa and Lo`ihi) are usually accompanied by numerous small earthquakes. They originate in regions of magma storage or along the paths that magma follows as it rises and moves prior to eruption. These are loosely termed volcanic earthquakes.
Many other earthquakes, including the largest ones, occur in areas of structural weakness at the base of Hawai`i’s volcanoes or deep within the Earth’s crust beneath the island. These are referred to as tectonic earthquakes. In the past 150 years, several strong tectonic earthquakes (magnitude 6 to 8 ) caused extensive damage to roads, buildings, and homes, triggered local tsunami, and resulted in loss of life. What follows is an overview of some of the more notable earthquakes that have occurred in Hawaii:
Much of the early record of Hawaiian earthquakes comes from the diary of Mrs. Sarah J. Lyman, a missionary’s wife at Hilo, on the Big Island of Hawaii. Mrs. Lyman began her account in 1833 and continued it until her death in 1885; this record was then continued for eleven more years by her descendants. About four or five earthquakes per year were reported.
On February 19, 1834, a strong shock threw down stone walls, stopped clocks, upset bottles, and sloshed milk out of half-full pans. Standing and walking were rendered difficult. A similar earthquake occurred on December 12, 1838. No volcanic activity was noted for either event.
On March 27, 1868, whaling ships at Kawaihae on the west coast of Hawaii observed dense clouds of smoke rising from Mauna Loa’s crater, Mokuaweoweo, to a height of several miles and reflecting the bright light from the lava pit. Slight shocks were felt at Kona on the west coast and Kau on the flanks of the volcano. On the 28th, lava broke out on the southwest flank and created a 15-mile flow to the sea. Over 300 strong shocks were felt at Kau and 50 to 60 were felt at Kona. At Kilauea the surface of the ground quivered for days with frequent vigorous shocks that caused lamps, crockery, and chairs to spin around as if animated. One shock resembled that of a cannon projectile striking the ground under the proprietor’s bed, causing him to flee, according to the narrative published by C. H. Hitchcock in the Bulletin of the Seismological Society of America in 1912. Between March 28, 1868, and April 11, over 2000 distinct shocks were felt at Kona.
The main shocks struck on April 2, at 4:00 p.m., and again on April 4 at 12:30 a.m. A magnitude of 7 3/4 was estimated for this earthquake (by Augustine Furumoto in his February 1966 article on the Seismicity of Hawaii in the Bulletin of the Seismological Society of America) based on the extent of intensity reports. Instrumental recordings, the usual basis for computing magnitudes, were not available at this early date. The shock was felt throughout the islands as far as Niihau some 350 miles away. The ground rolled like a ship at sea and many walls tumbled down. A landslide three miles long and thirty feet thick swept down the hill carrying trees, animals, and men. Thirty-one people and thousands of cattle, sheep, horses, and goats were killed in the one slide. A seawave struck the coast from Hilo to South Cape, being most destructive at Keauhou, Puna, and Honuapo; 180 houses were washed away, and 62 lives were lost to the wave alone. A 10-foot-high wave carried wreckage inland 800 feet. Not a house survived at Honuapo. A stone church and other buildings were destroyed at Punaluu. Maximum wave heights were 65 feet, the highest observed on Hawaii to date. (More on this earthquake.)
An intense earthquake occurred on January 22, 1938, with a magnitude on 6 3/4 and a maximum intensity VIII on Mauna Loa. The epicenter, located under the ocean about 40 miles east of the island of Molokai, was about as far north as earthquakes occur in the Hawaiian chain. On Maui there was general panic with people rushing from theaters. Flashing lights were reported by many. Landslides blocked roads and cut water pipes. Several reservoirs and water tanks were damaged. A chimney fell and a transformer was thrown down at Hana. Windows were broken and walls were cracked at Kula.
It was felt widely on the other islands with some damage on Molokai (pipes broken), Lanai (bottles thrown from shelves), Oahu (organ pipes out of sockets at Honolulu and the seismograph at the University was dismantled), and Hawaii (dishes broken, some chandeliers fell). The earthquake was distinctly felt by two ships at sea.
A severe earthquake occurred on August 21, 1951, and had a maximum intensity of IX and a magnitude of 6.9. Scores of homes were wrecked or damaged on the Kona coast on the west side of Hawaii. Rocks fell from cliffs, causing a 12-foot wave. A landslide covered the famed Pali Kapu o Keoua burial grounds of Hawaiian royalty. Cracks six inches wide opened on th coastal highway. Walls of churches were thrown down in Hookena and houses moved from their foundations at Napoopoo and Kealakekua. Telephone service was out through most of the area. The collapsing of water tanks along the dry Kona coast faced with a two-month dry season made it necessary to truck water from Hilo.
Scores of small earthquakes are reported felt each year.
For more information, visit the website of the Hawaiian Volcano Observatory.
Destructive Earthquakes in Hawai`i County Since 1868 *
Epicenter Maximum No of Date Location Intensity Mag Deaths Damage
03 28 1868 Southern Hawai`i IX 7.0 0 Extensive-Southern Hawai`i. 04 02 1868 Southern Hawai`i XII 7.9 81 >100 houses destroyed, tsunami 10 05 1929 Hualalai VIII 6.5 0 Extensive-Kona 08 21 1951 Kona VIII 6.9 0 Extensive-Kona 04 26 1973 North of Hilo VIII 6.2 0 Extensive-Hilo, $5.6M 11 29 1975 Kalapana feature VIII 7.2 2 Extensive-Hilo, $4.1M 11 16 1983 Ka`oiki IX 6.7 0 Extensive-Southern Hawai`i, >$6M 06 25 1989 Kalapana VII 6.2 0 Southeast Hawai`i almost $1M 10 15 2006 Kiholo Bay VIII 6.7,6.0 0 NW Hawai`i, >$100M