Earthquakes
Geology
Oceanography
Volcanology
JPL
SolarViews
StarDate
Spring 21 March - Vernal Equinox Summer 21 June - Summer Solstice Autumn 23 September - Autumnal Equinox Winter 21 December - Winter Solstace
Earth's atmosphere
Barometric Formula
Earth throws a wobbly [The Chandler Wobble] - 18/07/00 A mysterious wobble that shakes the Earth as it spins on its axis is caused by pressure changes at the bottom of the ocean