The Development of Ancient Earthquake Instruments

This paper studies sensing element designs in ancient seismometers and describes the developments of ancient earthquake instruments. A basic seismograph comprises a seismometer, a recording system, and a timing system. The major difficulty in the development of a seismograph was the design of the seismometer. And, the break through was the use of a pendulum system as a sensing element that responded to ground motion and did not move with the ground. Early seismoscopes were primarily intended to determine that an earthquake had happened. The first seismoscope invented by Zhang Heng was Hou Feng Di Dong Yi made in ancient China around the year 132 AD. The truly successful seismographs were first designed and built in the 1880s by a group of British scientists in Japan. In 1906, Boris Galitzin developed a working electromagnetic seismograph with a great sensitivity. Finally, a comparison with the recording systems of ancient seismographs is concluded.

Luigi Palmieri: first scientific bases for geophysical surveillance in Mt. Vesuvius area

Luigi Palmieri (Faicchio 1807 -Naples 1896), was appointed Director of the Vesuvius Observatory in 1855. He rea1ized the first model of electromagnetic seismograph and the uninterrupted use at the Observatory of this instrument represented the first step towards a geophysical sensu strictu surveillance of Mt. Vesuvius area. Already at the end of the 18th century, Ascanio Filomarino had built a mechanical seismograph which was ab1e to record the amplitude of the seismic waves, the incoming direction of the earthquake and its starting time. In 1862 Michele Baldacchini proposed to the Neapolitan scientific community a question about the possibility to use the study of precursory signs of the Vesuvian eruptions to inform in advance people living near the vo1cano. Palmieri answered Baldacchini's request, giving proof of extreme far-sightedness from the scientific point of view but, similarly, much concreteness from the practica1 point of view: he described, with modern ideas, the things to do in order to carry out the surveillance in the Mt. Vesuvius area, but concluded thus: "Till we have not the (economic and instrumental) means we have spoken above, I think it is useless to entertain the Academy about the nature and the method of the observations and investigations to be performed".

The scientific life of Luigi Palmieri 100th Anniversary commemoration(21/04/1807-09/09/1896)

I present here a commemoration of the scientific life of Luigi Palmieri, II Director of the Osservatorio Vesuviano. His research on both volcanic and tectonic phenomena was supported by his development of the first electromagnetic seismograph, which he also built in a "portable" version. He had the intuition to relate seismic activity to eruptive episodes, and, in this sense, he was the first scientist to imagine the eruption forecast in a modern way.

Accuracy in LP electromagnetic seismograph calibration by least-squares inversion of the calibration pulse

abstract Uncertainties in the instrumental constants for the standard LP instruments of the WWSSN, arising from errors in amplitude measurements of the calibration pulse, are analytically quantified assuming that such measurement errors may be approximated by a perturbing Gaussian noise distribution. More importantly, for the practicing seismologist, uncertainties in magnification and phase delay of the entire instrumental transfer function are deduced from least-squares inversion of the seismogram calibration pulse. It is emphasized that reliable estimates of instrumental transfer functions are obtained by least-squares inversion of the calibration pulse, particularly for underdamped or near critically damped seismographs, where the Gaussian noise distribution is the dominant source of error.

A note on the calibration of the electromagnetic seismograph

abstract Explicit expressions are given for the response in the time domain of a zerocoupled seismometer-galvanometer combination for a step of acceleration as initial conditions. The results may be directly applied for computing the system parameters.

Benndorf's formula for the dynamic magnification of an electromagnetic seismograph

The indicator equation for a seismogram from an electromagnetic seismograph is integrated under the assumption that the trace has the form of a suddenly beginning sinusoid. An expression for the velocity sensitivity is derived from the integrated result and applied to the particular case of a seismometer-galvanometer combination with natural frequencies of 2 Hertz-200 Hertz respectively. For that seismograph the dynamic velocity sensitivity at transducer—earth resonance is one-fifth of the steady-state harmonic sensitivity at resonance.