The Bardarbunga volcano in Iceland continues to show signs of stirring, but it's unclear what type of eruption, if any occurs at all, will take place. According to the latest information from the Icelandic Meteorological Office and other Icelandic government agencies, more than 700 earthquakes were recorded from midnight through 10 a.m. local time, indicating that hot magma was moving within the volcano, which lies beneath a glacier.

Most of the new earthquakes have centered along the tip of a dike of newly formed rock that the magma is creating as it flows northeastward, approaching the edge of the Vatnajokull (Dyngjujökull) glacier, which is the largest glacier in Europe. According to the statement on the Met Office website, the dike beneath the glacier, like a freshly laid magma pipeline, is now about 22 miles long and contains a whopping 300 million cubic meters of magma, or about 79 billion gallons.

Scientists have not directly measured this flow of magma, since it lies underground and beneath ice that in some areas is hundreds of feet thick. Instead, they have inferred the amount from measurements using GPS equipment, which they have been installing near the volcano, as well as computer models. "Additional stations for continuous GPS monitoring will be installed... within a few days," the Met Office says.

Earthquakes during the past 48 hours, as of August 25, 2014, associated with the Bardarbunga Volcano. Image: Icelandic Meteorological Office

Reached via Twitter, Ben Edwards, an associate geology professor at Dickinson University, says the total amount of magma in the dike is larger than what erupted from the Eyjafjallajokull and nearby volcanoes in 2010, but cautioned that "for sure only a small percentage (10-30% at most) of magma in [the] dike would likely erupt." Edwards said Mount St. Helens in Washington state erupted about 1,000 cubic meters of lava during its explosive eruption in 1980.

Some scientists are speculating that some of the magma may be moving toward other volcanoes in the area through linkages that haven't been previously detected.

So, it looks like the earthquake swarm that started under Bardarbunga might be headed towards Askja to the north. — Erik Klemetti (@eruptionsblog) August 25, 2014

So far, though, the intense seismic activity observed since August 6 is somewhat of a scientific mystery that is giving researchers an opportunity to learn more about Iceland's ever-shifting geology. Since August 23, there have been more than 2,500 earthquakes of various sizes, mainly small tremors, recorded in and around the volcano. And according to the Met Office, "there are no indications that the intensity of the activity declining."

So maybe the two magmatic systems - Bardarbunga and Askja - are linked at depth. Pure speculation on my part. — Erik Klemetti (@eruptionsblog) August 25, 2014

The researchers and government officials monitoring the volcano laid out three different scenarios, each of which would have very different consequences for Iceland and international aviation, since airborne volcanic ash is harmful to jet engines. The 2010 eruption of the Eyjafjallajokull volcano forced more than 100,000 flights to and from Europe to be canceled.

Here are the three scenarios from the Met Office:

The migration of magma could stop, attended by a gradual reduction in seismic activity. The dike could reach the surface of the crust, starting an eruption. In this scenario, it is most likely that the eruption would be near the northern tip of the dike. This would most likely produce an effusive lava eruption with limited explosive, ash-producing activity. An alternate scenario would be the dike reaching the surface where a significant part, or all, of the fissure is beneath the glacier. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.

The Met Office cautions that other scenarios "cannot be excluded." An orange aviation alert remains in effect, indicating the possibility of air travel disruptions due to an eruption, but since an eruption is not yet in progress, a red alert hasn't been issued again since it was dropped on Sunday. Scientists had initially thought that lava was leaving the volcano and making contact with the overlying glacier, which would have been known as a subglacial eruption, but they later determined that was not occurring, at least not yet.

"For example, an eruption inside the Bardarbunga caldera is possible but presently considered to be less likely," the Met Office said. A caldera is a crater-like land feature that is usually formed from an explosive volcanic eruption, and Bardarbunga is a type of volcano, known as a stratovolcano, that is prone to developing calderas because of successive explosive and more muted eruptions.

Stratovolcanoes are a common type of volcano. Iceland is a volcano hot spot because it is located at the boundary between the North American plate and the Eurasian plate, which are splitting apart in a tectonic divorce. This boundary is known as the Mid-Atlantic ridge, and at that ridge, molten rock, or magma, rises to fill the gap between the plates. This occurs to a greater degree in Iceland than elsewhere along the ridge because of other unique geological features.

Iceland has around 30 volcanoes, and experiences a volcanic eruption approximately once every five years, according to Nature News. Iceland has been the site of massive eruptions throughout history, including the 1783 eruption of the Laki volcano, which cooled the globe for several years by putting so much ash and sulfur particles into the upper atmosphere, reflecting incoming solar radiation.