Universität zu Köln

Hinzen, Klaus-G. (2012). Rotation of vertically oriented objects during earthquakes. J. Seismol., 16 (4). S. 797 - 815. DORDRECHT: SPRINGER. ISSN 1573-157X

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Abstract

Vertically oriented objects, such as tombstones, monuments, columns, and stone lanterns, are often observed to shift and rotate during earthquake ground motion. Such observations are usually limited to the mesoseismal zone. Whether near-field rotational ground motion components are necessary in addition to pure translational movements to explain the observed rotations is an open question. We summarize rotation data from seven earthquakes between 1925 and 2009 and perform analog and numeric rotation testing with vertically oriented objects. The free-rocking motion of a marble block on a sliding table is disturbed by a pulse in the direction orthogonal to the rocking motion. When the impulse is sufficiently strong and occurs at the 'right' moment, it induces significant rotation of the block. Numeric experiments of a free-rocking block show that the initiation of vertical block rotation by a cycloidal acceleration pulse applied orthogonal to the rocking axis depends on the amplitude of the pulse and its phase relation to the rocking cycle. Rotation occurs when the pulse acceleration exceeds the threshold necessary to provoke rocking of a resting block, and the rocking block approaches its equilibrium position. Experiments with blocks subjected to full 3D strong motion signals measured during the 2009 L'Aquila earthquake confirm the observations from the tests with analytic ground motions. Significant differences in the rotational behavior of a monolithic block and two stacked blocks exist.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Hinzen, Klaus-G. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-482132
DOI:	10.1007/s10950-011-9255-6
Journal or Publication Title:	J. Seismol.
Volume:	16
Number:	4
Page Range:	S. 797 - 815
Date:	2012
Publisher:	SPRINGER
Place of Publication:	DORDRECHT
ISSN:	1573-157X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language POINT REYES STATION; SAN-FRANCISCO EARTHQUAKE; CENTRAL ITALY EARTHQUAKE; GROUND ACCELERATIONS; ROCKING RESPONSE; NEAR-FIELD; MOTION; ANOOSHEHPOOR,A.; SEISMOMETER; HEATON,T.H. Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/48213