Abstract. Intense crises of crustal stress appear to cross large regions, and to precede by several months the eventual occurrence of some strong earthquake within them. The phenomenon is not linear, and the stress control reflects some wide scale-size rather than local effects. The stress propagation through the crust can be effectively monitored by means of acoustic emission (AE) techniques (ultrasounds). The correlation is here investigated between crustal stress crises and the total release of seismic energy within some space domain around the AE recording site. Some clear inferences can be envisaged, although a significant diagnosis of the state of the crust within a given region ought to request arrays of simultaneously operated AE recorders. Some case histories are described dealing with the Italian peninsula and with the Cephallonia Island.

No abstract

Considerable important research in upper atmosphere geophysics is carried out through the use of arrays of ground‐based magnetometers. In order to better delineate the ionospheric and magnetospheric currents and waves as measured by these arrays, it is important to understand the conductivity of the earth's structure under the individual stations. Geomagnetic depth sounding studies are used to deduce the earth's conductivity profiles. In most studies, ‘induction arrows,’ or ‘induction vectors,’ are plotted on maps for graphical representations of lateral inhomogeneities in underground conductivity structures. Different methodologies and different arrow conventions have been used by a number of authors for deriving these vectors, often without relating their techniques to other work in the field. We review herein the various methodologies (except transfer functions) and present a unifying picture to the representations that should prove useful to researchers in both space physics and solid earth physics.

No abstract

A concise threefold illustration is given: (i) of climate change on the gigayear (Ga) time scale through the nanosecond (nsec) time scale, (ii) of the role of the performance of solid materials, concerning both manmade and natural structures with reference to security, and (iii) of the exploitation of the electrostatic energy of the atmospheric electrical circuit—which is an enormous reservoir of natural “clean” energy. Several unfortunate misunderstandings are highlighted that bias the present generally agreed beliefs. The typical natural pace of the Earth’s “electrocardiogram”, ~27.4 Ma, is such that, at present, for the first time humankind must challenge an Earth’s “heartbeat”. A correct use of sensors is needed to get an efficient monitoring of the ongoing climate change. Both anthropic and natural drivers are to be considered. A brief reminder is given about sensors that ought to monitor solid materials—with application (i) to every kind of machinery, building, viaduct or bridge, vehicle, aircraft, rocket, etc. and (ii) for a correct (and unprecedented) monitoring of the electric field at ground, which is the prerequisite for the exploitation of the electrostatic energy of the atmosphere. In every case, a systemic approach is always needed. Every specialized investigation often misses the true physics of phenomena. The resulting great complication can be tackled by means of suitable approximate and “simple” models, which always have to be correctly tested. The impact on the biosphere is manifested as a steady regeneration of microorganisms at the deep ocean floors, supplied by endogenous CH4. Microorganisms are thus the beginning of an ever rejuvenating food chain. The natural climate change implies a permanent evolution of living forms. On the longer time-scale, a permanent cycle occurs of species extinction and/or generation. In addition, owing to such a process, some living forms are likely to also exist underground on other planetary objects. That is, life ought to be a ubiquitous intrinsic endogenic feature of matter in the universe, while life’s survival, evolution and/or extinction, ought to depend on the available hosting environment.