In the scene in Cafe Diem when Henry is showing Zoe how to melt pennies with sound, after Jack comes into the café, the penny on the plate is whole again.
When Allison and Carter are talking in the street, the cars change whenever the camera pans. When it's looking at Allison it's a grey car, when it pans to Carter it's orange.
In the long shot as Dr. Mendel picks up a beaker with blue liquid in it , you can see the beaker is full but in the close up shot it only has a tiny amount in it.
When Dr Hood falls in the mine, he injures his left arm. But later, he has a sling on his right arm.
A fumarole is an eruption of steam and gas, not mud.
Zoe's homework is to calculate electron mass, but electron mass is a constant.
Komatiite magma has an extremely rare composition, and was only produced on Earth in the Archean eon (earlier than 2.5 billion years ago). It could not be produced by melting pre-existing rock.
The premise for the episode relies on the idea that Eureka was built where it was due to a lack of seismic activity. However, clues point to Eureka being in Western Oregon, thusly in the Cascadia subduction zone, which has been due for a massive earthquake for years. The Cascades mountain range also is home to several volcanoes, most notable being Mt St Helens, whose massive 1980 eruption was referenced in a later episode.
When Carter and Allison are talking in the street, behind them you can see a sign for Home Hardware, a Canadian hardware store.