Mauna Loa: Hawaii
Mauna Loa is a shield volcano on Hawaii s Big Island.Mauna Loa (4169m, 13679ft) means "long mountain" in Hawaiian and is earths largest volcano by volume a massive 75,000km2 of lava thats 88,000 cubic miles. It sits next to its neighbour Mauna Kea on Big Island.
The Geology bit
Mauna Loa is thought to be 700,000 years old and emerged from the ocean 400,000 years ago. The summit caldera is 5km by 2.4km with walls of 180m. Most of the activity within the last 150 years has been from flank eruptions. It is one of the worlds most active volcanoes and has erupted 39 times in the last 150 years. It last erupted in 1984 when a lava flow headed towards the city of Hilo.Some lava flows from the volcano can be 40km long. Quite a few attempts at lava diversion have been made in 1935 and 1942 when lava flows were bombed from the air to divert or stop the flows entering Hilo. The flows stopped but the bombing was not thought to have been the cause and was not tried in 1984. In 1880 the Hawaiin Princess Ruth or Luka made offerings to pele at an advancing lava front and it stopped!
In 2002 increased seismic activity and movement of the cladera walls has begun to indicate a reinflating of a magma chamber 5km for the summit. Earthquake activity was high until 2004 when it slackened off.The magam chamber inflation rate has steadied and no eruption seems imminent at present.
What to see and How to see it?
Mauna Loa is not as accessible as Kilauea but you can reach the top with effort! the Mauna Loa road stops at 6662 feet up and is where the Mauna Loa summit trail begins. From here it is 19 miles to the top and will take a 4 day round trip. The air will thin as you ascend and it will get a lot colder. There are no tourist trappings here so you must pack in and pack out.
Alternatively and less strenuously you can take the 50 mile saddle road between Mauna Loa and Mauna Kea which crosses Big Islands Kona coast to Hilo. Althought paved most car rental companies won't let you take your car over the road. You may be able to negotiate if you hire a 4WD.USGS: Mauna Loa: Current Activity
National Park Service: Mauna Loa trail advice
Summitpost.org: Mauna Loa trail description