On mechanical Q parameters of the lower mantle inferred from data on the Earth’s free oscillations and nutation

Earth's free oscillations excited by the 2011 TohokuMw9.0 earthquake detected with a groundwater level array in mainland China

“…Free oscillations of the Earth have been used to constrain and provide insight into the Earth's deep interior structure and its dynamics (Ness et al 1961;Laske & Masters 1999;Woodhouse & Deuss 2007;Molodenskii & Molodenskaya 2009;Molodenskii 2010), to understand the focal mechanisms of earthquakes (Kanamori & Anderson 1975;Park et al 2005;Lambotte et al 2007;Okal & Stein 2009;Bogiatzis & Ishii 2014) and to recognize slow and silent earthquakes (Beroza & Jordan 1990). Theories of the Earth's free oscillations which have been discussed since the latter part of the 19th century were gradually verified by experimental observations during the late 1950s and 1960s.…”