Hawaiian volcanoes - interesting facts

The Hawaiian Islands are actually the peaks of large volcanoes that have been raised from the ocean floor. Thus, for example, the biggest island of Hawaii, "Big Island", which is two times bigger than all other Hawaiian islands together, was formed by accumulation of material ejected from five volcanoes, whose eruption overtaking each other.
Two of the five volcanoes are still active, so the process of building the island is still ongoing.
One of the volcanoes, Mauna Loa, has eruptions every few years. In 1950, his eruption lasted for 23 days. Throughout this period the hot-lava flashed down the slopes of the volcano into the sea. Sea water was boiling, so many fish had died.
Another volcano - Manua Kea - is extinguished. It is also the highest mountain in the Pacific. It rises over 4,135 meters above sea level, but its base reaches 5,400 meters below the surface rail to the ocean floor. If we would measure the underwater base, than this volcano would be the highest mountain in the world.
On the island of Maui is the Haleakala volcano, about 3,075 meters high. It is the largest dead volcano in the world. Its crater is about 32 kilometers in extent and its depth is 716 meters.