Volcano Watch — Pillow fight helped America win its independence

The United States gained its full independence through a war that lasted eight years, killing over 50,000 soldiers due to fighting and disease. It was a tough, bloody campaign, with the Americans struggling in the first years of the war. Things started to turn around for independence-minded colonists, however, with the Battle of Saratoga in upstate New York in 1777. The Americans had a special advantage over the British in that battle: pillow lava.

The Revolutionary War was two years old in 1777, with mixed results for both British and American forces and no clear outcome in sight. The British hatched a plan to end the war by splitting the rebellious colonies down the middle, sending General John Burgoyne's army from Canada, south through the Champlain Valley (along the east border of New York State), to connect with British troops moving north from New York City.

Burgoyne's army fought their way down through New York but encountered stronger American resistance near the village of Saratoga in September. The Battle of Saratoga actually consisted of two battles fought over a month, with the American army eventually gaining the advantage and pushing Burgoyne's army back towards the north. But Burgoyne's army was still fit to fight another day, and the American army needed to capture it for a decisive victory. That's where the pillow lava comes in.

American General John Stark, stationed north of the retreating British, worked to cut off their retreat. He hastily positioned his men beside (and probably atop) a steep hill of unusual rock next to the Hudson River. The hill provided both an ideal lookout and, importantly, a bottleneck with the Hudson River that could be used to ensnare the retreating British. The Americans lay in wait, ready to spring the trap….

General Stark's soldiers might have noticed that the rock they were on was unusual but not that they were on an ancient formation of pillow lava. The lava was erupted over 400 million years ago, as part of the first stages of plate collision that formed the Appalachian Mountains. At that time, plate tectonic motion was pushing an island arc, similar in shape to Japan, into the east coast of North America. Buckling and tearing of the crust triggered volcanic activity beneath the shallow ocean near the coast, oozing out lava onto the sea floor. Lava erupted underwater tends to form distinct lobes, or "pillows," and the resulting formations are called pillow basalts. Eventually, the lava cooled, and continued uplift during this collision pushed the lava out of the water.

You may have seen video of pillow lava forming, resembling thick, spiny black toothpaste oozing out from incandescent cracks under water. With Kīlauea currently sending lava into the ocean near Kupapa‘u Point, pillow lava is probably forming southwest of Kalapana at this very moment.

As the American army was encircling the retreating British, the last avenue of escape for the British was through the gap between the hill of pillow lava and the Hudson River. With General Stark occupying this narrow pass, he essentially "locked the back door," and the British army was surrounded. The plan had worked perfectly.

Burgoyne surrendered on October 17, and the Battle of Saratoga was won decisively by the Americans. The victory not only provided a morale boost and ended the British plan to split the colonies, it also demonstrated that the American colonists had the potential to defeat the British. Further, this event persuaded France to openly support the American independence cause. The battle is often considered the turning point of the American Revolution, and the humble hill of pillow lava that helped make it all happen is now known as Stark's Knob.

Who could have guessed that lava oozing onto the sea floor almost a half billion years earlier could have such an impact on the formation of our country? As you celebrate this July 4, think about how American independence was facilitated by a hill of pillow lava.

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Volcano Activity Update

A lava lake within the Halema‘uma‘u Overlook vent produced nighttime glow that was visible from the Jaggar Museum overlook and via HVO's Webcam during the past week. The lava lake level during the past week started off at roughly 40–45 m (130–150 ft) below the floor of Halema‘uma‘u, but then began dropping slightly with minor summit deflation around Monday, June 24.

On Kīlauea's East Rift Zone, breakouts from the Peace Day tube remain active at the base of the pali and on the coastal plain. Small ocean entries are active on both sides of the Hawai‘i Volcanoes National Park boundary. The Kahauale‘a 2 flow, fed from a spatter cone on the northeast edge of the Pu‘u ‘Ō‘ō crater, continues to advance slowly along the edge of the forest north of Pu‘u ‘Ō‘ō.

There was one earthquake reported felt in the past week across the Hawaiian Islands. On June 21, 2013, at 12:04 a.m., a magnitude-4.5 earthquake occurred 55 km (34 miles) north-northeast of Maunaloa, Moloka‘i, at a depth of 34 km (21 mi).