The Ground Should Not Move

Earthquakes on the Big Island 1962-1985

Growing up in the mid-Atlantic region and going to college in Washington, DC, I am not accustomed to the ground suddenly deciding to move.  Hawai'i, however, has earthquakes.  Last night, there were 2.  My California friends will probably tell me to pipe down since the earthquakes, which struck off the coast of Maui, were only magnitudes 4.7 and 3.3.  I recognize these are small, but when I was sitting in my bed at 6:31pm last night, I thought my roommate was home having sex and shaking the wall.  Turns out, she wasn't.  There was a small earthquake.  The bed only shook for a second and was only enough to confuse me.  But I did notice.  I did a little research and it seems I will have to get used to this craziness.  Hawaii has a lot of small earthquakes.

One of the best things about an earthquake though is it gives me something to write on an otherwise boring day.  Pretty soon I am going to have to talk about my job, which will surely get my 2 readers to stop reading.  I also get to give fun facts!  Earthquakes in Hawai'i are closely linked to volcanoes. They are an important part of the island-building processes that have shaped the Hawaiian Islands. Thousands of earthquakes occur every year beneath the Big Island alone.

Crustal Plates

Hawai'i is geologically a unique place because it is caused by a "hot spot." Most islands are found at tectonic plate boundaries.  There are few "hot spots," though and the one under Hawaii is right in the middle of one of the largest crustal plates on Earth - the Pacific Plate. A geologic "hot spot" is an area in the middle of a crustal plate where volcanoes form (see picture at very bottom of blog) when molten magma breaks through the crustal plate. A hot spot is why Yellowstone National Park has geysers.  Eruptions and magma movement within the presently active volcanoes (Kilauea, Mauna Loa and Lo`ihi) are usually accompanied by numerous small 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.