Intensity and isoseismal map of 25th November 2007 Delhi earthquake

An earthquake of magnitude ML: 4.3 occurred on 25th November 2007 (2312 UTC) in Delhi with hypocenter at 28.56° N / 77.08° E and focal depth 33.1 km. The epicenter was at about 21 km SW of Delhi University. It was widely felt in and around Delhi and created panic among the local populace. A macroseismic survey was conducted in about ten days starting from 27th November, 2007 at 89 locations covering an area of about 1500 sq. km in Delhi and its neighborhood through a questionnaire. The results of the macroseismic survey allowed establishment of spatial distribution of the earthquake effects in the form of isoseismal map generated using geo-statistical analysis tool of ArcGIS 9.1. The isoseismal map shows that most parts of Delhi region experienced an intensity of V on MMI scale, except on northern most region of Delhi where intensity was found IV. The mean isoseismal radii for the zones V, IV, III and II are 29.13, 57.78, 83.63 and 100.75 km, respectively. The orientation of elongated epicentral track of intensity field shows that the stress release was pronounced along Delhi-Sargodha ridge and earthquake was attributed to activities of this ridge.

Comparative Parametric Analysis of Opening Area Usage of Shear Wall in Different Percentages Relating to Wall Area Used for Multistorey Building

It is highly recommend that the structure should be efficient in terms of the cost in diverse manner. To reduce the overall cost of the project, the cost cutting should be done in every construction stages. The dual systems in building structure consist of structural walls and moment resisting frames. The structural wall members are made up of RCC, which is a costly structural member. The purpose of current study is to explore the reduction in shear wall area in multi-storey building for reduction of overall project cost. Total 5 buildings abbreviated as SOA, SOB, SOC, SOD and SOE framed in analytical software supposed to be situated at Seismic Zone III. After the comparative result analysis, it proves that, the reduction in shear wall area should be adapted to a certain limit due to load transfer criteria of the members 20 % wall deduction is sufficient. Building SOD with 80% coverage performs best of all. Keywords: Deduction Area, Earthquake Effects, Opening Area, Shear Wall, Response spectrum, Wall Area Reduction, Wall Deduction Ratio.

Earthquake effects and insights on fault activity at the Beatrice Cenci cave (Abruzzo, Central Apennines)

he focus of this study is the analysis of a cave in Central Italy, the Beatrice Cenci cave, in order to point out and constrain evidence of possible past earthquakes and of fault activity in the area. We performed a survey of seismic related damages within the cave. This included the analysis of broken/collapsed speleothems, the recognition of structural collapse, of tilting/growth alteration in the speleothems, and the mapping of fractures, joints and/or faults. To timely set the occurrence of the recognized damage, organic sediments were dated with 14C radiocarbon method. The results merged toward the recognition of two distinct seismic shaking events affecting the cave environment, one older than 30 kyr and another around 7 kyr. The deformation observed within the cave led us to the hypothesis that the events of damage were possibly linked to the activity of the regional tectonic lineament that crosses the cave, i.e., the Liri normal fault. The morphology and the evolution of the cave appear controlled by the fault zone. These speleoseismological results provided a new contribution on the knowledge of the past activity of the Liri fault and on the earthquake history of this sector of Central Apennines.

Between Necessity and Legal Responsibility: The Development of EEWS in Italy and its International Framework

Earthquake Early Warning Systems (EEWSs) represent a technical-scientific challenge aimed at improving the chance of the population exposed to the earthquake shaking of surviving or being less affected. The ability of an EEWS to affect the risk and, in particular, vulnerability and exposure, may determine serious legal responsibilities for people involved in the system, as scientists and experts. The main question concerns, in fact, the relationship between EEWSs and the predictability and avoidability of earthquake effects-i.e., the ground shaking affecting citizens and infrastructures - and the possibility for people to adopt self-protective behavior and/or for industrial infrastructures to be secured. In Italy, natural disasters, such as the 2009 L’Aquila earthquake, teach us that the relationship between science and law is really difficult. So, before EEW’s become operational in Italy, it is necessary to: 1) examine the legislative and technical solutions adopted by some of the international legal systems in countries where this service is offered to citizens; 2) reconstruct the international and European regulatory framework that promotes the introduction of EW systems as life-saving tools for the protection of the right to life and understand whether and how these regulatory texts can impose an obligation on the Italian legal system to develop EEWS; 3) understand what responsibilities could be ascribed to the scientists and technicians responsible for managing EEWS in Italy, analyzing the different impact of vulnerability and exposure on the predictability and avoidability of the harmful event; 4) reflect on the lessons that our legal system will have to learn from other Countries when implementing EEW systems. In order to find appropriate solutions, it is essential to reflect on the opportunity to provide shared and well-structured protocols and creating detailed disclaimers clearly defining the limits of the service. A central role must be recognized to education, because people should not only expect to receive a correct alarm but must be able to understand the uncertainties involved in rapid estimates, be prepared to face the risk, and react in the right way.

Integrating macroseismic intensity distributions with a probabilistic approach: an application in Italy

The geographic distribution of earthquake effects quantified in terms of macroseismic intensities, the so-called macroseismic field, provides basic information for several applications including source characterization of pre-instrumental earthquakes and risk analysis. Macroseismic fields of past earthquakes as inferred from historical documentation may present spatial gaps, due to the incompleteness of the available information. We present a probabilistic approach aimed at integrating incomplete intensity distributions by considering the Bayesian combination of estimates provided by intensity prediction equations (IPEs) and data documented at nearby localities, accounting for the relevant uncertainties and the discrete and ordinal nature of intensity values. The performance of the proposed methodology is tested at 28 Italian localities with long and rich seismic histories and for two well-known strong earthquakes (i.e., 1980 southern Italy and 2009 central Italy events). A possible application of the approach is also illustrated relative to a 16th-century earthquake in the northern Apennines.

Obtaining a Real Natural Numerical Landslide Model by Comparing Measurement and Predicted Values: A Case Study of Kavşakbendi̇ Dam Left Bank Andirap Landslide

The Andırap landslide is located on the left bank of the Kavşakbendi dam approximately 50 km from the Kozan district of Adana province in Turkey. After it was determined that the mass stability was impaired during the dam construction work, the landslide movements were followed by surface geodetic measurements and inclinometers. According to the measurements that were taken, displacements totaling 0.10 m were measured between 2010 and 2017, and it was determined that the speed of movement slowed considerably between 2017 and 2020. In this study, the results of stress-strain and stability analyses were evaluated taking into account the soil model created based on extensive site and laboratory research to examine the sliding mechanism of the Andırap landslide mass. After the numerical model was verified using site measurements, the movements of the landslide mass were examined by numerical analyses, taking into account the different loading conditions that may be encountered during the service life of the dam. According to the results of the analysis, no global slide was observed for the slip circle of the Andırap landslide and in the analyses conducted for the situation where the reservoir is full, the deep displacement of 0.11 m was consistent with the average displacement of 0.04 and 0.11 m deformation values measured from inclinometers. In the analyses carried out for the loading condition featuring a full reservoir and earthquake effects, it was calculated that shallow displacements reached up to 1.0 m, but deep displacements were 0.13 m.

Performance of externally bonded fiber-reinforced polymer retrofits in the 2018 Cook Inlet Earthquake in Anchorage, Alaska

As part of the effort to improve the seismic performance of buildings in Alaska (AK), many of the deficient structures in Anchorage, AK, were retrofitted—some with externally bonded fiber-reinforced polymer (EBFRP) composite systems. The 2018 magnitude 7.1 Cook Inlet earthquake that impacted the same region offered an opportunity to evaluate the performance of EBFRP retrofits in a relatively high-intensity earthquake. This study summarizes the following findings of this field investigation: (1) the performance of EBFRP-retrofitted structures in the Cook Inlet earthquake and (2) the observations concerning the condition of FRP retrofits from over a decade of exposure in a subarctic environment. A deployment team from the National Institute of Standards and Technology (NIST) in collaboration with the University of Delaware (UD) Center for Composite Materials conducted post-earthquake inspections of EBFRP retrofits in multiple buildings to assess their performance during the earthquake and condition with respect to weathering. EBFRP debonding was documented with infrared thermography and acoustic sounding and the bond quality between EBFRP and concrete was assessed using pull-off tests. Visual inspections showed no major signs of earthquake damage in the EBFRP-retrofitted components. However, evaluation of debonding and pull-off test results suggested that outdoor conditions may have led to bond deterioration between EBFRP and concrete from installation defects that grew over time, freeze–thaw expansion from moisture present at the FRP/concrete interface, differences in thermal expansion of the materials, or a combination thereof. The carbon fiber–reinforced polymer (CFRP) bond to concrete was found to be more vulnerable to outdoor exposure than the glass fiber–reinforced polymer (GFRP) bond. Earthquake effects on FRP/concrete bond could not be assessed due to the lack of baseline data.