Over the weekend, Kilauea volcano's lava lake reached its highest point in over a year.

On Sept. 10, the Hawaiian lava lake inflated to within 16 feet of the lake's rim, the highest the lake has been since May 2015 when the lake actually reached the rim. This increase in lake depth corresponded with an increase in seismic activity, including two magnitude-3.1 earthquakes. As you can see in the video's archive footage, high levels in the lake can cause the lava to splash and splutter into the shore.

By Sept. 11, however, the lake was beginning to deflate, and the lake's level dropped to 66 feet below the floor of the Halema'uma'u Crater in which the lake resides. Scientists expect the lake to inflate again over the course of this week.

Inflation and deflation are normally terms we associate with balloons, but they're also used when it comes to explaining the behavior of Hawaii's volcanoes. Inflation occurs when magma rises up in the volcano's reservoir and, as a result, the ground around it begins to crack and break to accommodate the molten mass. In the lava lake's case, its level rises. While deflation normally occurs as a result of an eruption, it can also when magma gets funneled and stored in a rift zone, or fissures in the volcano's ground.

Kilauea's lava lake rises (and it's not done yet)
After reaching its highest point in over a year, the Kilauea volcano's lava lake deflated the next day. More fluctuations are expected.