Microseismicity related to gravity-induced slope deformations for risk management

An accelerometric array installed on 4 September 2008, has been used to manage the geological risk in the Peschiera Springs drainage plant of Rome's aque- duct, located in the Central Apennines approximately 80 km from Rome, Italy. The plant occupies a carbon- atic slope that is extensively involved in gravitational deformations, which are responsible for underground failures such as cracks and collapses of karst caves. To distinguish among different types of recorded events, an automated procedure was implemented taking into account duration, peak of ground acceleration (PGA) and its variation within the accelerometric array. The main sequence of underground failures so far recorded was related to the L'Aquila seismic sequence occurred in April 2009. Moreover, a very intense sequence of underground failures occurred in September 2011 that was not related to seismic events, i.e. only due to the gravitational processes affecting the slope. These evidences prove that the ongoing gravitational slope deformations have a key role in predisposing and/or causing the underground failures within the karst rock mass of the Peschiera Spring slope. A control index (CI) is daily computed as a func- tion of sub-indexes which are derived from the rate of cumulative Arias intensity of underground failures, the frequency of underground failures and the fre- quency of earthquakes. The CI index identifies "ordi - nary", "alert" or "emergency" levels of attention and represents a fundamental tool for managing the geo-

[1]  L. Lenti,et al.  Microseismicity within a karstified rock mass due to cracks and collapses as a tool for risk management , 2012, Natural Hazards.

[2]  R. Ando,et al.  A slow slip event triggered by teleseismic surface waves , 2011 .

[3]  Ik Siong Heng,et al.  Rotating stellar core-collapse waveform decomposition: a principal component analysis approach , 2008, 0810.5707.

[4]  Laurent Baillet,et al.  Analysis of Rock-Fall and Rock-Fall Avalanche Seismograms in the French Alps , 2008 .

[5]  G. Sottili,et al.  Effects of tidal stresses on volcanic activity at Mount Etna, Italy , 2007 .

[6]  A. Aronov,et al.  Characteristic features of induced seismic processes in mining regions exemplified by the potassium salt deposits in Belarus and Bulgaria , 2006 .

[7]  Meifeng Cai,et al.  In situ monitoring and analysis of rock mass behavior prior to collapse of the main transport roadway in Linglong Gold Mine, China , 2006 .

[8]  M. Miyazawa,et al.  Dynamic response of frequent tremors at Aso volcano to teleseismic waves from the 1999 Chi-Chi, Taiwan earthquake , 2005 .

[9]  S. Martino,et al.  From the geological to the numerical model in the analysis of gravity-induced slope deformations: An example from the Central Apennines (Italy) , 2005 .

[10]  S. Martino,et al.  Geological-evolutionary model of a gravity-induced slope deformation in the carbonate Central Apennines (Italy) , 2004, Quarterly Journal of Engineering Geology and Hydrogeology.

[11]  Xinglin Lei,et al.  Detailed analysis of acoustic emission activity during catastrophic fracture of faults in rock , 2004 .

[12]  T. Szwedzicki,et al.  Rock mass behaviour prior to failure , 2003 .

[13]  J. Kasahara.  Tides, Earthquakes, and Volcanoes , 2002, Science.

[14]  Xiaoning Stump B.W. Phillips W.S. Yang,et al.  Source mechanism of an explosively induced mine collapse , 1997, Bulletin of the Seismological Society of America.

[15]  B. Stump,et al.  Microseismicity induced by a controlled, mine collapse at White Pine, Michigan , 1997 .

[16]  J. A. Richards,et al.  Microseismic techniques for monitoring incipient hazardous collapse conditions above abandoned limestone mines , 1989, Quarterly Journal of Engineering Geology.

[17]  P. Davis,et al.  Tidal triggering of earthquake swarms at Kilauea Volcano, Hawaii , 1988 .

[18]  J. N. Hutchinson.  General report: morphological and geotechnical parameters of landslides in relation to geology and hydrogeology : Proc 5th International Symposium on Landslides, Lausanne, 10–15 July 1988V1, P3–35. Publ Rotterdam: A A Balkema, 1988 , 1988 .

[19]  W. Z. Savage,et al.  Mechanics of gravitational spreading of steep-sided ridges («sackung») , 1987 .

[20]  S. McNutt,et al.  Volcanic earthquakes at Pavlof Volcano correlated with the solid earth tide , 1981, Nature.

[21]  M. Johnston,et al.  Earth Tides and the Triggering of Eruptions from Mt Stromboli, Italy , 1972, Nature.

[22]  S. Bigi,et al.  Structural setting of the Cicolano-M. Calvo area (Central Apennines, Italy) , 2002 .

[23]  P. Bono,et al.  Schema Idrogeologico dell'Italia centrale: note illustrative e carte , 1986 .