Volcanic data shifted

[AnnikaLau]

The data used in Exercise 1.6 seems to be shifted. The peaks are one year after the volcanic eruptions.

[mathause]

I was intrigued by the question so I looked up the dates of the main eruptions:

• Krakatoa: August 1883
• Santa Maria: October 1902
• Novarupta: June 1912
• Agung: February 1963 to January 1964
• El Chichón: April 1982
• Pinatubo: June 1991

Although the peak is in the year after the eruption, the levels are already higher than the base in the year of the eruption. As many of the volcanoes erupted later in the year and stratospheric sedimentation is slow, it might be correct this way (but then again that's not my area of expertise).