Main Article Content
the theory related to the rotation fi eld and its association with seismic waves. There can be many different causes
leading to observed/recorded rotation effects; we can group them as follows: generation of micro-displacement
motion due to asymmetry of source processes and/or due to interaction between seismic body/surface waves and
medium structure; interaction between incident seismic waves and objects situated on the ground surface. New
recording techniques and advanced theory of deformation in media with defects and internal (e.g., granular) structure
make it possible to focus our attention on the fi rst group, related to microdisplacement motion recording, which
includes both rotation and twist motions. Surface rotations and twists caused directly by the action of emerging
seismic waves on some objects situated on the ground surface are considered here only in the historical aspects
of the problem. We present some examples of experimental results related to recording of rotation and twist
components at the Ojcow Observatory, Poland, and L'Aquila Observatory, Italy, and we discuss some prospects
for further research.
No Permission Required
Istituto Nazionale di Geofisica e Vulcanologia applies the Creative Commons Attribution License (CCAL) to all works we publish.
Under the CCAL, authors retain ownership of the copyright for their article, but authors allow anyone to download, reuse, reprint, modify, distribute, so long as the original authors and source are cited. No permission is required from the authors or the publishers.