Ozone Emitted From Eyjafjallajökull Just as Magma Approached the Surface

The ozone anomaly formed during the time shown by the red shaded area just as surface displacement around Eyjafjallajökull (colored dots with error bars) began to change quickly and the number of earthquakes began to increase. Black shows the daily number of earthquakes, grey the cumulative number. The first eruption of lava was on March 20. Based on Figure 2 of Sigmundsson et al. (2010).