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Active aseismic creep on the Alto Tiberina low-angle normal fault, Italy

Sigrun Hreinsdottir and Richard A. Bennett
Active aseismic creep on the Alto Tiberina low-angle normal fault, Italy
Geology (Boulder) (August 2009) 37 (8): 683-686

Abstract

The existence of active low-angle normal faults has been questioned because the standard theory of fault mechanics precludes normal faults from slipping at low (<30 degrees ) dip angles, and there is an apparent deficiency of large normal fault earthquakes globally with a shallow dipping fault plane. The Alto Tiberina fault, Italy, is a low-angle normal fault (with dip 15 degrees -20 degrees ) that has been clearly imaged with seismic reflection profiles and is highlighted by microseismicity. The fault is thought to be the main structure accommodating extension in the region. However, few large earthquakes have been documented on or near the fault for more than 2 ka. Analysis of data from a recently established network of continuous global positioning system (GPS) stations in the Umbria-March region, Italy, shows that the Alto Tiberina low-angle normal fault in the Northern Apennines is actively slipping at a shallow depth within the brittle crust. Crustal deformation models that best fit the GPS are consistent with both a shallow dip and active, mostly aseismic, creep of approximately 2.4+ or -0.3 mm/a below 4+ or -2 km locking depth along the Alto Tiberina fault.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 37
Serial Issue: 8
Title: Active aseismic creep on the Alto Tiberina low-angle normal fault, Italy
Affiliation: University of Arizona, Department of Geosciences, Tucson, AZ, United States
Pages: 683-686
Published: 200908
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 50
Accession Number: 2009-072355
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2009165
Illustration Description: illus. incl. sect., sketch map
N42°00'00" - N44°00'00", E10°00'00" - E14°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200939
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