Volcanoes in Hawaii
When one hears of Hawaii, images of grass-skirted ladies, pineapple recipes, tanned people on beaches and great big waves for surfing generally come to mind. However, one of its other main attractions is its volcanoes. In fact, the archipelago is known for its “Hawaii Volcanoes National Park,” which boasts of the biggest volcano in the world. Tourists can view the volcanoes and hike to craters but the lava activity and eruptions are closed to visitors. This area is on the east of the part and is hazardous. (see: http://www. nps.
gov/havo/planyour visit/lava2. htm) Being volcanic in nature, Hawaii can greatly affect its surroundings because of the eruptions and underground volcanic activities. The daily formation or development of volcanoes can cause tsunamis and landslides which can be devastating depending on their impact on land. Hawaii’s islands are situated towards the south of a volcanic chain estimated to have been formed 70 million years before. part of the archipelago more known as Hawai’i, has five known volcanoes namely Mauna Loa, Kilauea, Hualalai and Lo’ihi.
Another volcano, Haleakala, that may have erupted in the 1700s is on another island, Maui. The History of Volcanoes in Hawaii The Islands of Hawaii exist because of volcanic activity. Each of the islands of this territory can each boast of its own particular volcano although some are parts of just one. If one is going to look below the sea, he or she would be surprised to see that the islands are just the tips of volcanoes that have gone past the surface of the ocean. Hawaiian volcanoes are considered “shield” volcanoes because of its slope.
Shield volcanoes usually have smooth gentle slopes because of the lava that helps mold it. Other volcanoes on earth can emit lavas or magma with more silica and are usually characterized by more viscous, thicker, shorter lava flows; with thick blocky deposits or great spurts of ash that fall from the sky after explosive eruptions. (see: http://www. nps. gov/havo/planyour visit/ lava2. htm) Thus, these kinds of volcanoes are steeper and the slopes rougher. Hawaii’s volcanoes typically emit basalt, a type of rock that is very high in liquidity when it becomes melted.
Because of this characteristic of basalt, lava flows gently on the slopes of the active mountain to make them smoother. Below is a map that was made to show the sea floor beneath the Hawaiian archipelago: This map was funded and spearheaded by the Japan Marine Science and Technology Center (JAMSTEC) in cooperation with the U. S. Geological Survey (USGS) and other institutions of both countries. The lava flows documented in history are indicated in red while the orange and yellow parts show the past sizes of the islands (ex.
O’ahu is much smaller now compared to how great it used to be). The map also shows fields of “blocky debris” which is assumed to have been caused by devastating landslides that could have forced huge pieces of the volcanoes to as far as 200 kilometers away on the sea floor. (see: (http://geopubs. wr. usgs. gov/i-map/i2809/) The ages of the volcanoes on the archipelago was observed to have a pattern which led to the discovery that these volcanic formations are depended on the movement of the North Pacific Ocean’s sea floor.
The Pacific Ocean’s floor, also known as the Pacific Plate, is a tectonic plate above a layer of the Earth called Asthenosphere. When the Pacific Plate moves over the part of the Asthenosphere where magma is formed, new volcanoes can strike through the Pacific plate. When this happens, an island is formed. As the plate constantly moves northwestward, the volcanoes wane in eruptive activity as new ones are being formed. Once activity stops, erosion slowly decreases the size of the islands until it will finally go beneath the sea surface. (See: http://www. soest. hawaii.
edu/GG/HCV/haw_formation. html) The Volcanoes Mauna Loa. In native tongue, Mauna Loa means “long mountain” and it is rightfully called so. Its summit caldera is called Moku’aweoweo wherein “moku” refers to a land on the coast and asweoweo is a type of red fish. Although the literal translation is fish land but they say that the imaginative image being provoked is a flow of lava. Scientists consider the Mauna Loa as the largest volcano on earth. Its heavy weight causes the sea floor to depress for another 8 kilometers and the mountain extends to another 5 kilometers beneath the sea surface.
The Mauna Loa’s towers to 4 kilometers and spans 120 kilometers if our basis would be the part we see above the sea. However, it is truly about 17 kilometers high and encompasses half of the Big Island if it is measured from the sea floor. Mauna Loa is a very active volcano with 33 recorded eruptions. The first of its recorded eruptions happened in 1843 and its last was in March 24 to April 15 of 1984. The dimension of the caldera is 3 x 5 kilometers elongated northeast-southwest. It is 183 meters deep and was estimated to have collapsed about 600 to 750 years ago.
Its oldest dated rocks are found to be about 100,000 to 200,000 years old and scientists are guessing that the volcano’s first eruption happened 1,000,000 to 700,000 years ago. In 1984, Mauna Loa erupted and threatened the lives of 40,000 people in Hilo. The lava flowed up to 6. 5 kilometers before it reached the city. However, these residents should not have been shocked for Hilo is deemed to be situated on the lava flows that were produced by the same volcano in 1881. (See: http://www. ngdc. noaa. gov/seg/cdroms/geohazards_v3/document/ 739005. htm) Kilauea.
The youngest Hawaiian volcano is Kilauea which means “spewing” or continuous spreading. The volcano got its name because of its almost ceaseless flow of lava. The caldera of the volcano has no particular name but its crater, Halema’uma’u means “house full of ferns. ” Legend says that the volcanic goddess Pele had a suitor in the person of Kamapua’a who got jilted and tried to contain Pele by making a house of ferns. However, stories say that Pele escaped Kamapaua’a’s ploy which explains the consistent volcanic eruptions. For many years, scientist thought that Kilauea was just a part of Mauna Loa because of its proximity to each other.
However, a few decades ago, researchers found out that the volcano is equipped with a magma-plumbing system that goes as far as 60 kilometers deep from what is visible on land. Hawaiians used to refer to Kilauea as only the summit caldera part until research was finally able to correct this notion which made them include the whole volcano. The Kilauea erupted last 1983 and still continues to spew lava from the Pu’u O’o cone or the highest point. The lava that comes from the cone is directed through a tube system down to Pulama Pali which is about 11 kilometers toward the sea.
The first to documents the volcano was Reverend William Ellis who saw it in 1823. The caldera rarely ceased activity until the early part of 21st century. There have been 34 eruptions recorded since 1952 totaling to 61 recorded in history. The the start of the most current eruption happened in 1983 and until now, the volcano still explodes. Because of its relentlessness, Kilauea is tagged by some as one of the earth’s most active volcanoes. The caldera is 6 x 6 kilometers but its main depression is 3 x 5 kilometers. The caldera is 165 meters deep.
The age of the caldera is estimated to be 500 to 210 years ago while the oldest dated rocks are 23,000 years old. Its earliest subaerial eruptions may have happened 50,000 to 100,000 years ago. Scientists believe that Kilauea may have first erupted about 300,000 to 600,000 years ago. Although no deaths have really been recorded in any of the recent explosions of Kilauea, the lava flows have destroyed many residential and farm areas. In 1960, the whole village of Kapoho was ruined because of an eruption at the lower east rift of Kilauea while the Royal Gardens and Kalapana were seriously damaged in its 1980 explosion.
(See: http://www. ngdc. noaa. gov/seg/cdroms/geohazards_v3/document/ 739005. htm) Hualalai. Hualalai is the third youngest and third-most historically active volcano in Hawaii. (see: http://hvo. wr. usgs. gov/volcanoes/hualalai/) Lava erupted from six different parts of this volcano since the 1700s to 1801. The west part of the island suffered lava flows from Hualalai twice. In fact, the Keahole Airport is on top of one of its former flows. Although this volcano is not as active as the two already mentioned, more than three quarters of the mount’s surface has been encompassed by lava flows which must have accumulated for 5,000 years.
The oldest dated rocks found on this volcano dates to about 128,000 years ago. It is estimated that the Hualalai must have grown above sea level about 300,000 years ago. In 1929, a dangerous swarm of earthquakes rocked the locals for more than a month. This was caused by rising magma. In the past years, however, many people have built their homes and businesses on the outskirts of Hualalai even though this volcano is predicted to erupt again after a century. Lo’ihi Seamount. “Lo” in Hawaii mean long which is a term coined for the volcano in 1955 that aptly describes the elongated shape of the Lo’ihi.
Lo’ihi Seamount is on the sea floor of Hawaii and is about 30 kilometers away from the land. Its height is about 969 meters. Although the volcano was thought to have never had an eruption, it has been the source of many earthquakes. Its most intense swarm of quakes consisted about 4000 that jiterred the island in August 1996 Lo’ihi’s summit has a depression but scientists do not consider it a caldera. This has a dimension of 2. 8 x 3. 7 kilometers wide. It has three craters on the southern part which are formed by its earthquake swarms.
The most recent crater, created in 1996, is called Pele’s Pit and had a diameter of 600 meters and depth of 300 meters. Lo’ihi’s base on the north is approximately 1,900 meters below sea level while the southern part is 4,755 meters below se level. The highest point is estimated to be 931 meters from its northern sea floor and 3,786 meters if taken from the southern part. (See: http://hvo. wr. usgs. gov/volcanoes/loihi/) The swarm of earthquakes in 1996 triggered scientists to research on the activity of the seamount and they were surprised to find out that Lo’ihi has erupted. This was the first recorded explosion of the volcano.
Scientists were able to gather sulfides and amorphous silica coatings in the lavas and sediments. (See: http://www. soest. hawaii. edu/GG/ HCV/loihi-summary. html) Haleakala. Haleakala literally means “house of the sun. ” According to myth, the demigod, Maui, caught the sun when it was on top of this mountain and made the blazing ball of fire slow down its movement in the sky. Although Haleakala’s last volcanic eruption must have occurred towards the end of the 18th century, scientists believe that this East Maui volcano has had many eruptions in the past and hypothesize that there could have been around ten in the last ten centuries.
However, there are newly obtained radiocarbon ages suggesting that the last eruption may have happened between 1480 to 1600. (See: http://hvo. wr. usgs. gov/volcanoes/haleakala/) Because of this unpredictability and sporadic activity in very long spans of time, researchers also believe that it can erupt again in the future. The lava flow on Haleakala must be around 1. 1 million years old. Scientists reveal that volcanoes beneath the sea surface tend to take 600,000 years. Haleakala is hypothesized to have been growing for 2 million years.
Most of volcanic activity in the East Maui area are concentrated along the southwest and east rift zones. These two zones create a curving arc that starts from the southwestern, La Perouse Bay through the Haleakala Crater to Hana at the eastern side. This pattern proceeds east under the ocean as to what is called the Haleakala Ridge, one of the longest rift zones of Hawaii. The part of this alignment that is exposed on land can be very dangerous because of its possibility of spews of cinder and lava. (see: http://hvo. wr. usgs. gov/volcanoes/haleakala/) Haleakala Crater is on the summit of this volcano.
On its northwest and southeast regions are large valleys that lead to the north and south beaches. The dimensions of the crater are 3. 5 x 12 kilometers shaping east-west with a depth of 860 meters. Conclusion Hawaii is very rich in volcanoes because it stands on a hot spot of volcanic chains. Its own existence can be attributed to the result of many volcanic eruptions millions of years ago. Although the government has opened these mounts to the public as a tourist attraction, some parts remain unsafe because of continuous activity that may not be visible because of its origins beneath the land and sea levels.
Being along a volcanic chain not only poses danger because of lava but also due to the earthquakes that are being caused by these mounts. Another negative factor going for the Hawaiian residents is the continually changing landscape they face which get reduced because of erosion as can be seen in the history of the islands. Nature can be very ironical. It has made Hawaii very known for its beaches and great waves that are so ideal for surfing. However, beneath this cool surface lies a hot spot that can trigger an earthquake or volcanic eruption at anytime.Just like people, Hawaii can be cool upfront but pretty dangerous when it blows its top.
1996 Loihi Science Team, 22 July 1998, 1996 Seismic/Volcanic Event Summary, Hawaii Center for Volcanology (from http://www. soest. hawaii. edu/GG/HCV/loihi- summary. html) Eakins, B. W. , Robinson, J. E. , Kanamatsu, J. N. , Smith, J. R. , Takahashi, E. & Clague, D. A. , 2003, Hawaii’s Volcanoes Revealed, U. S. Geological Survey Geologic Investigations Series I-2809. ( http://geopubs. wr. usgs. gov/i-map/i2809/) East Maui, or Haleakala-A Potentially Hazardous Volcano, 20 February 2003, U.
S. Geological Survey ( http://hvo. wr. usgs. gov/volcanoes/haleakala/) Hawaii Center for Volcanology, The Formation of Hawaiian Islands, ( http://www. soest. hawaii. edu/GG/HCV/haw_formation. html) Hawaii Volcanoes National Park, 29 October 2007, National Park Service (http://www. nps. gov/ havo/planyourvisit/lava2. htm) Hawaiian Volcanoes, 18 June 2001, United States Geological Survey ( http://hvo. wr. usgs. gov/volcanoes/) Hualalai Hawaii’s Third Active Volcano, 18 June 2001, United States Geological Survey. (http://hvo. wr. usgs.
gov/volcanoes/hualalai/) Kilauea-Perhaps the Most Active Volcano, 2007, United States Geological Survey. (http://hvo. wr. usgs. gov/kilauea/) Lockridge, P. , Racey, S. , & McLean, S. , 1997, Geologic Hazards Photos User’s Manual, National Geophysical Data Center, (http://www. ngdc. noaa. gov/seg/cdroms/ geohazards_v3/document/739005. htm) Lo’ihi Seamount Hawaii’s Youngest Submarine Volcano, U. S. Geological Survey, ( http://hvo. wr. usgs. gov/volcanoes/loihi/) Mauna Loa, 02 February 2006, United States Geological Survey, ( http://hvo. wr. usgs. gov/Sample Essay of Eduzaurus.com