hawaii
Hawaii is a very unique place on Earth. This is due to the fact that it is located
right on the top of a hot spot. A hot
spot is a place where hot molten rock is pushed to the surface of the Earth and
causes volcanic activity. This is what led to the creation of Hawaii.
Hawaii has literally emerged from the seas. Hot spots push hot molten rock up into the surface of the Earth and create volcanoes under the sea. Over time these eventually build up and break through the water to form what we know as islands. They also create submarine mountains named seamounts. As the hotspot moves away from the plates, the volcanoes that were active become inactive because they no longer have the hotspot located under them, removing the source of heat and cooling the volcano down. When the lava in a volcano hardens, the rock that is formed is called "basalt". Hawaii is essentially a chain of massive volcanoes that are rooted to the ocean floor and joined together. Each of the Hawaiian islands are proof of the fact that the volcanoes must have had to erupt numerous times for them to be able to break the surface of the ocean and create the islands that we have today. Hawaii is located in the Pacific Plate. This plate changed direction 40 million years ago from north to northwest and is still slowly moving today at a rate of 3 and a half inches per year. The hotspot has been stationary for the last 40 million years under the island of Hawaii. This is how the islands first became to form 40 million years ago even though some were able to start developing 70 million years ago. Hawaii consist of 8 major islands. These are Hawaii, Maui, Oahu, Kauai, Molokai, Lanai, Niihau, and Kahoolawe. These are all part of a bigger chain called the Hawaiian- Emperor Chain which is essentially a trail of volcanoes spread across the ocean floor. The oldest island of Hawaii is Kauai which formed 5.1 million years ago, then Niihau which formed 4.9 million years ago, then Oahu, Hawaii's third largest island formed 3 and a half million years ago, followed by Molokai which was formed 1 and a half million years, then Maui, Hawaii's second largest island formed a million years ago and lastly The Big Island of Hawaii which formed half a million years ago and is the youngest of the Hawaiian chain. Another volcano named Lo'ihi is being created currently and is expected to emerge from the seas in 10,000 to 100,000 years time as it is still 1000m below the ocean's surface and become an island. |
Volcanoes in hawaii
The Big Island of Hawaii has 5 volcanoes. The 5 volcanoes are Kilauea, Mauna
Loa, Mauna Kea, Hualalai and Kohala. 3 of them, Hualalai, Mauna Loa and Kilauea are still active as they have erupted in the last 200 years. Kohala is one million years old which
makes it the oldest volcano in Hawaii. However, it is currently inactive as it
stopped erupting 120, 000 years ago.
Mauna Kea is the tallest sea mountain in the world. It is actually 10, 000m higher than Mount Everest, however due to the Big Island weight, it sunk down and caused Mauna Kea to sink down with it. Mauna Kea erupted last 4,600 years ago however it is dormant as it is expected to erupt again. It also has a variety of habitats which are home to several species only found in Hawaii. Hualalai rose from the ocean 300,000 years ago. It is also dormant currently however it is the third most active volcano in Hawaii with it lasting erupting during 1800-1801 and expected to erupt every few hundred years. Mauna Loa is the largest volcano in the world. It is also taller than Mount Everest however again, due to it's weight, it sunk down into the seafloor. It is also a very active volcano with it having erupted 39 times, and the last eruption being in March-April 1984. It is expected to have erupted once every 6 years since 3000 years ago. Due to the fact that it is a very active volcano, it is surprising that it hasn't erupted since the last 30 years however it is believed that it is due for an eruption soon. Kilauea is the youngest volcano in Hawaii. It is the most active volcano in Hawaii and is ranked in the most active volcanos in the world due to the fact that it erupts every few years. It has been erupting constantly since 1983 and is currently undergoing one of the world's longest-lived eruptions. Since 1952 however, it has had 36 eruptions with 90% of the surface of Kilauea only being about 1000 years old. This volcano invites about 2 million visitors each year because of the chance to see active lava with your own eyes. |
EARTHQUAKES IN HAWAII
As Hawaii is located directly in the Pacific Plate, it cannot have earthquakes caused from tectonic plate movements on the borders of plates. Earthquakes in Hawaii are therefore very closely linked to volcanic activity. This is due to the fact that they result from the same process that volcanoes and the island itself are built through. The eruptions and the movement of the magma within the volcano can also cause small earthquakes and occur quite often. The magma that moves through the ground puts great force into the rocks that are surrounding it and this causes the rocks to release all their energy because they cannot handle the stress and produce the earthquake. The Pacific Plate can also be bent from the weight of the volcanos resting on it and can be another cause for the earthquakes to occur. Earthquakes are usually measured in magnitude or intensity with an earthquake of magnitude 5 being moderate, 6 strong, 7 major and 8 as a "great quake".
There are reports of thousands of earthquakes occurring under the Big Island of Hawaii. Many of the thousands of earthquakes that occur are quite small and can't be felt, therefore only being detected by seismometers however some are so strong that they can be felt even in other islands.
The worst and largest recorded earthquake that Hawaii has experienced was on the 2nd of April, 1868 when a 7.9 magnitude earthquake struck the Big Island of Hawaii and 81 people died. It was extremely violent in the southern part of Hawaii and moderate in the Maui island next to it. There was also smoke seen rising from the Mauna Loa volcano. In the following weeks, 2000 shocks were felt. the earthquake also generated an tsunami that was approximately 18m high and that resulted in another 46 deaths.
The probability of a earthquake with a magnitude of 6.5 or worse is more and more likely in the following years. In the next 50 years, there is a 97% chance that an earthquake of that magnitude will hit the Hawaiian islands.
There are reports of thousands of earthquakes occurring under the Big Island of Hawaii. Many of the thousands of earthquakes that occur are quite small and can't be felt, therefore only being detected by seismometers however some are so strong that they can be felt even in other islands.
The worst and largest recorded earthquake that Hawaii has experienced was on the 2nd of April, 1868 when a 7.9 magnitude earthquake struck the Big Island of Hawaii and 81 people died. It was extremely violent in the southern part of Hawaii and moderate in the Maui island next to it. There was also smoke seen rising from the Mauna Loa volcano. In the following weeks, 2000 shocks were felt. the earthquake also generated an tsunami that was approximately 18m high and that resulted in another 46 deaths.
The probability of a earthquake with a magnitude of 6.5 or worse is more and more likely in the following years. In the next 50 years, there is a 97% chance that an earthquake of that magnitude will hit the Hawaiian islands.