David Gubbins

"Two recent studies of the geomagnetic field in the last 1Myr have found 14 excursions, large changes in direction lasting 5–10kyr each, six of which are established as global phenomena by correlation …"

"Earthquakes generate elastic waves when one block of material slides against another; the break between the two blocks being called a fault. Explosions generate elastic waves by an impulsive change in…"

"After a large earthquake the earth "rings" like a bell; this motion can be observed on sensitive instruments up to a month after a large event. These oscillations have specific frequencies which are p…"

"... since the Second World War ... the proton magnetometer has revolutionized measurements, satellites have given new impetus to magnetic surveying, discoveries of large mineral deposits have maintain…"

"Earthquakes radiate waves with periods of tenths of seconds to several minutes. Rocks behave like elastic solids at these frequencies. Elastic solids allow a variety of wave types and this makes the g…"