Seismic Hazard

Slip in the 2010-2011 Canterbury Earthquakes, New Zealand

by John Elliott

The 2010 MW 6.8 Yushu (Qinghai, China) earthquake: Constraints provided by InSAR and body wave seismology

by John Elliott

Depth segmentation of the seismogenic continental crust: The 2008 and 2009 Qaidam earthquakes

by John Elliott

The vertical separation of mainshock rupture and microseismicity at Qeshm island in the Zagros fold-and-thrust belt, Iran

by John Elliott

The 2009 L'Aquila earthquake (central Italy): A source mechanism and implications for seismic hazard

by John Elliott

The Sparta Fault, Southern Greece: Tectonic Geomorphology, Seismic Hazard Mapping and Conditional Probabilities.

by Giorgos Deligiannakis

Co-authored with Ioannis Papanikolaou, Gerald Roberts, Athina Sakellariou and Emmanuel Vassilakis

Long-term slip history discriminates among occurrence models for seismic hazard assessment

by Matthieu Ferry

GEOPHYSICAL RESEARCH LETTERS, 2010, VOL. 37, L20307, 5 PP.
doi:10.1029/2010GL044071

Today, the probabilistic seismic hazard assessment (PSHA) community relies on stochastic models to compute occurrence... more Today, the probabilistic seismic hazard assessment (PSHA) community relies on stochastic models to compute occurrence probabilities for large earthquakes. Considerable efforts have been devoted to extracting information from long catalogs of large earthquakes based on instrumental, historical, archeological and paleoseismological data. However, the models remain only and insufficiently constrained by these rare single-slip event data. Therefore, the selection of the models and their respective weights necessarily involves ruling by a panel of experts. Since cumulative slip data with high temporal and spatial resolution are now available, we propose a new approach to incorporate these pieces of evidence of mid- to long-term fault behavior into PSHA: the Cumulative Offset-Based Bayesian Recurrence Analysis (COBBRA). For the Dead Sea Fault, our method provides weights to the competing recurrence and rupture models, allows time-independent models to be ruled out, and provides a means to compute the cumulative probability of occurrence for the next full-segment event reflecting all available data.

Dynamic FE analysis of South Memnon Colossus including 3D soil-foundation-structure interaction

by Sara Casciati

Casciati S. and Borja R.I. (2004). “Dynamic FE analysis of South Memnon Colossus including 3D soil-foundation-structure interaction”. Computers & Structures, 82(20-21), 1719-1736. ISSN: 0045-7949.

DATE AND PLACE OF PUBLICATION: August 2004; Pergamon–Elsevier Science Ltd, Kidlington, Oxford OX5 1GB, Oxon, England.

ABSTRACT. A full three-dimensional dynamic soil–foundation structure interaction (SFSI) analysis of a famous landmark... more ABSTRACT. A full three-dimensional dynamic soil–foundation structure interaction (SFSI) analysis of a famous landmark in Luxor, Egypt, the South Memnon Colossus, is performed to investigate the response of this historical monument to seismic excitation. The analysis is carried out using the finite element (FE) method in time domain. The statue comprising the upper structure is modeled using 3D brick finite elements constructed from a photogrammetric representation that captures important details of the surface and allows the identification of probable zones of stress concentration. The modeling also takes into account the presence of a surface of discontinuity between the upper part of the statue and its fractured base. FE models of the foundation and the surrounding soil deposit are constructed and coupled with the statue model to analyze the seismic response of the entire system incorporating dynamic SFSI effects. These studies are useful for future conservation efforts of this historical landmark, and more specifically for designing possible retrofit measures for the fractured base to prevent potential collapse of the monument from overturning during an earthquake.

KEYWORDS: Soil–foundation–structure interaction; Multi-body deformable contact; Non-linear dynamic finite element analysis

Challenges to successful seismic retrofit implementation: a socio-behavioural perspective

by Temitope Egbelakin

DRIFTING AWAY FROM VS30: A PROPOSAL USING CONTINUOUS VS MEASURES FOR BUILDING CODES (PROPUESTA DE DEMANDA SÍSMICA CONTINUA PARA CÓDIGOS: ALEJÁNDONOS DE VS30)

by Gonzalo Montalva

Co-Authored with Fabian Soto (UdeC) and Adrian Rodriguez-Marek (Virginia Tech)

Most current building codes use average shear wave velocity over the upper 30 m as a parameter for classifying sites... more Most current building codes use average shear wave velocity over the upper 30 m as a parameter for classifying sites into discrete site classes. This paper discusses cases in which the use of discrete classes can be problematic. In addition, this paper
demonstrates that site response at some periods is better correlated to the average shear wave velocity over depths other than 30 m. In particular, for short periods, amplification correlates better with average shear velocity over shorter depths, which implies that better results are obtained with less information. This paper presents a proposal to use continuous measures of average shear wave velocity over period-dependent depths to determine seismic amplification factors for use in seismic codes. This methodology avoids the pitfall that two sites with slight differences in average shear wave velocity might be designed for
drastically different seismic demands.

Proposed Long Period Transition Map for New Indonesia Earthquake Resistant Building Code based on Indonesia Seismic Hazard Map 2010

by Usama Juniansyah Fauzi

Usama Juniansyah Fauzi, Achmad Fauzi, Masyhur Irsyam, F.X. Toha and
Hendriyawan

Proceeding of Annual International Conference Syiah Kuala University 2011
Banda Aceh, Indonesia, November 29-30, 2011

The new method for determining ground-motion parameters in the next edition of the Indonesian Earthquake Resistant... more The new method for determining ground-motion parameters in the next edition of the Indonesian Earthquake Resistant Building Code SNI 03-1726-X, which will be issued in this year, has significant changes than the old code. The major changes in SNI 03-1726-X are using Risk-Targeted Maximum Considered Earthquake (MCER) Spectral Response Acceleration maps. These maps developed by Team for Revision of Seismic Hazard
Maps of Indonesia were based on probabilistic approach for 2% probability of exceedance in 50 years and deterministic approach by using three-dimensional seismic source models and by considering latest geological and seismological data and fragility curve of buildings. For building design, it has been decided that ASCE 7-10 will be adopted for coming code SNI 03-1725-X. The design philosophy adopted from ASCE 07-10 standard contains a
significant addition consisting of a constant-displacement segment of the design response spectrum. This paper presents the proposed parameter TL developed by the author and Disaster Mitigation Research Center ITB (Pusat Penelitian Mitigasi Bencana ITB) to provide more realistic estimates of the ground motions at periods T > 4 sec by consisting a constant-displacement segment.

ESTIMATION OF SITE EFFECTS FOR VIJAYAWADA CITY

by Akhila Manne

Published in the conference proceedings of Indian Geotechnical conference -2011,"Geochallenges",Kochi,India.

Site effects play a major role in the seismic ground motion and have been ascertained by many seismologists
and... more Site effects play a major role in the seismic ground motion and have been ascertained by many seismologists
and earthquake engineers. Traditionally, direct waves were used for the site effect study (Gutenberg, 1957; Borcherdt, 1970)
but later it has been realized that the source, path and site characterization are the important parameters that affect earthquake
ground motion. Local site effects can cause considerable modification of seismic amplitudes. Depending on the ground
characteristics, the ground shaking is influenced, which may result in the amplification (causing resonance) or attenuation.
Nonlinear amplification at sediments sites appears to be more pervasive than seismologists used to think (Aki et.al., 1991).
Spectral amplification factor is a parameter which can be used to find out theses effects. Site effect is also an important
parameter in microzonation study. The information about the local site effects is useful in the simulation of strong ground
motions and hence, the results of the site response studies are one of the most important inputs for seismic hazard assessment
of a region. In this research paper, Vijayawada city which falls in zone III (IS 1893: 2002) has been considered for the site
response study. It is the 34th largest town in India (population wise), and the 3rd largest town in Andhra Pradesh. The shear
wave velocities and bulk density are used to estimate the average spectral amplification factor. Amplified site response at the
soft soil sites are obtained using the input shear wave velocities

Analysis of Single-Station Standard Deviation Using the KiK-net Data

by Gonzalo Montalva

published in Bulletin of the Seismological Society of America in 2011, co-authored with A. Rodriguez-Marek, Fabrice Cotton, and  Fabian Bonilla

Estimates of single-station standard deviation can be used as a lower
bound to probabilistic seismic hazard... more Estimates of single-station standard deviation can be used as a lower
bound to probabilistic seismic hazard analyses that remove the ergodic assumption
on site response. This paper presents estimates of single-station standard deviation
using data from the KiK-net network. The KiK-net network has a dense array of
stations that recorded a large number of earthquakes over the period of study, both
at the surface and at colocated borehole instruments. The large number of records
implies that there are a large number of stations with recordings from multiple events;
hence, site terms and single-station standard deviations can be properly estimated.
Borehole instruments permit a breakdown of residuals, considering the effect of
amplification in the shallow surface layers. Random-effects regression was first used
to develop a ground-motion prediction equation (GMPE) using both the surface and
borehole data. The GMPE was constrained such that event terms were the same at the
surface and borehole. Residuals were then computed and the within-event (intraevent)
residuals were separated into a repeatable site-term and a remaining residual, for both
the ground motion itself and for the empirical amplification factor between surface
and borehole. Results show that single-station standard deviations are considerably
lower than standard deviations using the ergodic assumption, and these standard
deviations are further reduced if only a small bracket of station-to-event azimuths
is considered for each station such that path variability is minimized. Moreover,
analyses of residuals indicate that most of the differences between ergodic standard
deviations of surface and borehole data are the results of a poor parametrization of
shallow site effects. However, the contribution of site-to-site variability in the empirical
amplification factor is only limited. Finally, a comparison with results from other
studies at different tectonic regions indicates that the values of single-station standard
deviations are strikingly similar for all studies.

Multilevel approach to large scale seismic vulnerability assessment of reinforced concrete buildings

by Maurizio Pollino

Paolo Ricci, Gerardo Mario Vederame, Maurizio Pollino, Flavio Borfecchia, Gaetano Manfredi
Proceedings XIV Convegno di Ingegneria Sismica - ANIDIS “Associazione Nazionale di Ingegneria Sismica” Bari 18-22 Settembre 2011

In this paper, a seismic vulnerability assessment at large scale is described, within the SIMURAI project. A field... more In this paper, a seismic vulnerability assessment at large scale is described, within the SIMURAI project. A field survey was carried out in order to gather detailed information about geometric characteristics, structural typology and age of construction of each single building. An airborne Remote Sensing (RS) mission was also carried out over the municipality of Avellino, providing a detailed estimate of 3D geometric parameters of buildings through a quite fast and easy to apply methodology integrating active LIDAR technology, aerophotogrammetry and GIS techniques. An analytical seismic vulnerability assessment procedure for Reinforced Concrete buildings is illustrated and applied to the building stock considering (i) field survey data (assumed as a reference) and (ii) LIDAR data combined with census data as alternative sources of information, according to a multilevel approach. A comparison between the obtained results highlights an acceptable scatter when data provided by RS techniques are used.

Global Positioning System (GPS) Determination of Motions, Neotectonics, and Seismic Hazard in Trinidad and Tobago

by Anthony Rodriguez

Co-authored with Dr. John C. Weber. Published in GVSU McNair Scholars Journal, 2008.

The twin island nation of Trinidad and Tobago is located in the actively deforming Caribbean-South American (Ca-SA)... more The twin island nation of Trinidad and Tobago is located in the actively deforming Caribbean-South American (Ca-SA) plate boundary zone. Geodetic GPS work over the past decade has accurately determined present-day Ca-SA relative plate motion. This work (Weber et al., 2001; Perez et al., 2001; Lopez et al., 2006) clearly shows the Caribbean plate today moves approximately eastward relative to the South American plate at ~20 mm/yr.

Earthquakes do not mark the active faults in Trinidad; however, a low-precision triangulation-to-GPS comparison at 23 sites showed that significant strike-slip faulting is probably occurring on the Central Range Fault (CRF) (Saleh et al., 2004). The lack of recent seismic activity on the CRF might indicate that the fault is elastically locked. Locked faults tend to store motion and then release it in infrequent big earthquakes, whereas creeping faults produce more continuous small earthquakes. A future large earthquake is therefore possible in our study area. Our research looks at Trinidad’s neotectonics using new GPS data from 19 high-stability sites that were built and measured in 2005, then measured again in 2007, and also includes data from a few sites that go back to 1994. These new data allow us to refine previous results from the lower-precision geodetic work. We intend to better quantify the rate of slip across the CRF and its mechanical behavior. We used campaign-style GPS field measurements collected by coauthor Weber and associates at the University of the West Indies. We compiled these data and processed them using GIPSY/OASIS II (Release 5.0) software at the University of Miami RSMAS Geodesy Lab. We find that in a South American reference frame sites north of the CRF move at about 20 (±1-5) mm/yr; sites south of the CRF are stationary (±1-8 mm/yr). Tobago site velocities are slightly oblique to the overall Caribbean plate motion due to a major (magnitude 6.7) earthquake that had occurred off Tobago’s south coast in 1997. Our results support the hypotheses that the CRF is an active strike-slip fault. We find that sites in Tobago and northern Trinidad are on the Caribbean plate and move at a rate of about 20 mm/yr eastward (relative to South America). Sites in southern Trinidad move slowly if at all relative to South America. We are fitting locked fault (elastic dislocation half-space) models to these data; this will allow us to look more closely at the mechanical behavior of the CRF and to establish whether it is locked or creeping to help evaluate its seismic hazard. This could be an important factor in determining the safety of citizens living in Trinidad and Tobago.

Coseismic displacements and Holocene slip rates for two active thrust faults at the mountain front of the Andean Precordillera (~33°S)

by Silke Schmidt

Schmidt, S., Hetzel, R., Mingorance, F. & Ramos, V.A. (2011) - Tectoncis, 30, TC5011, doi:10.1029/2011TC002932.

Resilient City and Seismic Risk: A Spatial Multicriteria Approach

by Beniamino Murgante

Tilio L., Murgante B., Di Trani F., Vona M., Masi A. (2011) “Resilient city and seismic risk: a spatial multicriteria approach” Lecture Notes in Computer Science vol. 6782, pp. 410–422. Springer-Verlag, Berlin. ISSN: 0302-9743, doi: 10.1007/978-3-642-21928-3_29.

Nowadays, the most common approach to seismic risk mitigation is characterized only by strategies reducing building... more Nowadays, the most common approach to seismic risk mitigation is characterized only by strategies reducing building vulnerability, through structural interventions, and it does not consider the possibility to intervene at urban scale, reducing urban seismic vulnerability. This paper deals with the concept of urban seismic vulnerability, and introduces resilience, as the capacity of a system to adapt itself to new, generally negative, conditions, in order to re-establish normal conditions. Each city can express resilience, and the identification of its elements is the goal of our research. A spatial multi-criteria approach is here proposed.

Keywords Resilient cities – Seismic Risk – Seismic Vulnerability – Urban Vulnerability – Spatial Multicriteria Analysis

Seismotectonic study of Central Greece and Hypocenter relocation using the double-difference algorithm

by Andreas Karakonstantis

31st General Assembly of the ESC 2008, poster session SEMR-1-PATTERNS, Oral & Poster Abstracts, pg.57

Earthquake relocation in Greece using a unified and homogenized seismological catalogue

by Andreas Karakonstantis

Co-authored with Papadimitriou P.

Bull. Geol. Soc. Greece, Proceedings of the 12th International Congress, Patras, May, 2010, pg.2043-2052.

Active deformation in the broader area of the western Corinth gulf (Greece)

by Andreas Karakonstantis

Co-authored with Papadimitriou P , Agalos A, Moshou A, Kapetanidis V, Kaviris G, Kassaras I, Voulgaris N and Makropoulos K, 2010. 32nd General Assembly of the ESC 2010, Oral & Poster Abstracts, pg. 54