Hawaii’s volcanoes form on a chain called the Hawaiian Emperor Seamounts chain, a series of hotspots that are located in the sea. The hotspots reach a peak, forming a shield, then they die out, reappearing along the trail to create a new eruption. Tuzo WILSON developed this theory in 1963. The earliest hotspots date back to 5.1-billion-years old volcano on Kauai. The “Big Island” has been a focal-point in the field of volcanic science for 400,000 years. The younger age of the island supports the hotspot hypothesis, since it is the most active on the chain.
The first stage of the shield volcanic cycle is called the submerged pre-shield. The submarine vents are responsible for this. Submarine shields are formed when the low-volume material is accumulated into rising earth. During this time the magma is cooling and it deteriorates the calderas. The shield is able to rise above the original ocean bed because this pattern keeps repeating and recycling. When the volcano reaches sea level, oxygen is exposed and more eruptions occur. Sub-aerial stage: the eruptions are less violent and more frequent. It is possible to see a shield-like formation above sea level as the magma cools. In the post-shield phase, the eruptions are much larger and sticky than during the sub-aerial stage. The rejuvenated phase is where there are small eruptions and the lava plumes can be seen infrequently. The coral isoll stage marks the end for the volcano. The volcano is eroded and shattered by activity and erosion to the sea level. This is what is seen on Kauai.
Five volcanoes are located on the Big Island. Kohala’s age is estimated at one million years. However, the oldest rock that has been recorded as being emitted is only about 460,000 years. Kohala is a zone that poses less of a risk due to the last eruption occurring 120,000 year ago. Kohala had a major experience when the post-shield was revealed. A massive landslide sent debris 81miles out to sea. This volcano traps lava with low viscosity. Large faults are the main geographic feature, which was caused by a landslide. The shield has been completed and the land is now in post-shield. This period has lasted for 245,000 of its years. After completing its shield stage, the land has been able for life to flourish. The lava-covered floor is covered with a thick layer of moss, which traps rainwater. This ecosystem is the most flourishing on the island, with 155 native species.
Mauna Kea also exists on the island of Hawaii and is a volcano with similar fissures to Kohala. Its most distinctive features are its cinder conical shape and glacial activity. The most recent evidence of explosive eruptions is the cinder cones. They are aged between 4500-9000 years. The small temperature drops during the last glacial period allowed snow to accumulate on the volcano’s peak. Snow has formed moraines in the caldera. Moraines are soil and sand deposits. The most windy, alpine and rocky environment found on the island is ideal for research.
Haulalai’s most notable eruption is the 1801 large one. Lava poured out of the collapsed northwestern rift zone and flowed to the northwest, west and southwest. First, the lava flowed 16 km towards the present-day Kona International Airport. Second, the lava flowed 6km to the sea. Second, there was the 1929 quake swarm. This geological anomaly saw thousands of tiny earthquakes triggered by small magma motions under the volcanic cone. The event, which caused damage of $100,000, was the last indication of volcanic activity that threatened Haulalai. At least one earthquake of magnitude 4 occurs in the region every year.
Mauna Loa occupies a large part of the big island’s landmass. Mauna Loa is the world’s largest volcano and occupies over? The lava has built up a large, steep caldera that has caused the peak to reach a height 13 679 feet. Its lava reaches the ocean eight time since 1868. It has had 33 eruptions, the last of which was in 1984. The vogs that accompany these eruptions can be quite thick. It is possible that the magma could become unstable causing a flank to be disrupted. Mauna loa caused a magnitude 8 in 1868, and a 7.2 magnitude in 1975. Scientists also believe that tsunamis are generated by the seismic activity.
Kilauea is the fifth volcano on the island. It’s the most active volcano in the world. This volcano, which is located on the big island, has a very unpredictable eruption pattern, despite the short pause between 1934-1952. According to research, the rock is between 300,000 and 600,000 years. This makes it the youngest part of the island. This bulge appears to be on the flanks of Mauna Loa. There is some volcanic and earthquake activity that comes from this neighboring area. Its most recent caldera, which is about 500 years old, is in the shield stage. The volcanic ecosystem has been changed by frequent eruptions. Acid rain is created when precipitation and volcanic ash, which contains sulfur dioxide, mix. Tephra and volcanic ash also cause soil contamination, which prevents plant growth. Three of nine Hawksbill Sea Turtle nesting areas are located on the coast. It is becoming a greater concern in terms of the environment, and biologically. This is due to the increasing frequency and size of eruptions.
Hawaiian lava consists of a feldspar rich trachyte that contains 65% silicon. Scientists have an interest in this type of lava, as it is present on every island and not just the biggest one. According to the United States Geological Survey, the biggest island volcanoes are classified as follows: Mauna Loa, Kilauea, Haulalai 4, Mauna Kea 8, and Kohala 9. The higher the number is the lower the overall risk. The geological information and volcanic activity on the island are fascinating. A new shield is forming along the Emperor Seamount Chain. This zone has been named Lo’ihi. All five volcanoes are in contact and together form the largest and most populated island along the chain. This is a great example of how geological processes create islands around the world.