Strong motion record processing of the Baikal rift zone

The work is devoted to the adaptation of the earthquake record processing algorithm of the Pacific Earthquake Engineering Research Center to the peculiarities of seismic monitoring of the Baikal region. A tool for forming a database for building a regional seismic attenuation model is presented.

Earthquake record processing algorithms to form a strong motion database

This study is devoted to the development of algorithms and software for earthquake record processing. The algorithms are based on the methodology used by the Pacific Earthquake Engineering Research Center for the implementation of the scientific project NGA-West2. The purpose of processing is to determine reliable values of ground acceleration and other parameters of earthquakes from the available records of velocity time series. To analyze the operation of the algorithms, earthquake records (simultaneously recorded time series of acceleration and velocity) taken from the European Rapid Raw Strong-Motion database were used. The developed algorithms and the implemented software will allow in the future to form a database of strong motions for building regional attenuation models on the territory of the Russian Federation.

The Study of Automatic Picking of P and S Wave Arrival and Identification of Earthquake Sequence Pattern using Scalogram in Obspy (Python)

Initial identification on an earthquake record (seismogram) is something that needs to be done precisely and accurately. Moreover, the discovery of a series of unexpected successive earthquake events has caused unpreparedness for the community and related agencies in tackling these events. Determining the arrival time of the P and S waves becomes an important parameter to finding the location of the earthquake source (hypocenter) as well as further information related to the earthquake event. However, manual steps that are currently often used are considered to be less effective, because it requires a lot of time in the process. Continuous Wavelet Transform (CWT) analysis can be a solution for this problem. With further CWT analysis in the form of a scalogram, can help to determine the arrival time of P and S waves automatically (automatic picking) becomes simpler. In addition, further CWT analysis can also be utilized to help identify the sequence of earthquake events (foreshock, mainshock, aftershock) through the resulting scalogram pattern.

Study on Tuned Mass Damper Use in High-Rise Building

Current styles in the construction industry demand tall and light buildings, which are also flexible and low-cost. This increases the chances of failure and problems from the point of view of usability. Many modern methods are available to reduce structural vibration, with many vibration control strategies, the idea of using the new TMD. This study was conducted to study the efficacy of using TMD in controlling structural movement. Initially a numerical algorithm was developed to investigate the response of a shear structure containing TMD. Next another numerical algorithm was developed to investigate the response of an independent 2D model programmed with TMD. Three slow loading methods used. The first was a sinusoidal upload, the second was in line with the corresponding timeline according to IS-1894 (Part -1): 2002 with 5% erosion (PGA = 1g) and the third was 1940 El Centro Earthquake Record (PGA) = 0.313g). From research it has been found that TMD can be used effectively to control building vibrations. TMD worked best when the softness of the structure was low. Gradually increase the magnitude of the effects of TMD on the gradual decline in the response to structural migration. Keywords: Harmonic absorber, viscous damper, crankshaft torsional damper, kinetic energy,

Innovative EC8-compliant solutions for selection of the optimum retrofitting scheme of buildings with special characteristics

This article presents the seismic assessment and retrofit design of an existing old building in Greece of great regional importance. The Building is the “Administration building of Kalamata” located in the city of Kalamata, capital of the Messinia Prefecture. The Building, the largest in the city, is a seven-floor reinforced concrete (r/c) structure with a basement built in 1974. The seismic assessment procedure is based on the provisions of the EN 1998-3 code and the Greek code for structural interventions “KAN.EPE.,” introducing several novelties that give solutions to difficult practical problems with respect to the modeling, the analysis methods, and performance evaluation framework. The article presents details of the Building’s modeling, description of the analyses, and the corresponding results, as well as the most efficient retrofitting schemes that fulfill the safety demands (i.e. performance level B or “Life safety” and performance level C or “Collapse prevention” according to KAN.EPE.), considering cost and minimal disturbance both for the superstructure and foundation interventions. While considering the various intervention solutions, it proceeds with new simplified ways that optimize the proposed solution. As such, it can be used as a paradigm for finding clever, practical, and at the same time economical solutions. An interesting characteristic of the Building is that it has been strengthened already after the damaging earthquake of 1986, but the new usage requirements raised questions about the adequacy of that earlier strengthening. Last, but not least, it must be mentioned that this building is unique in the sense that the main earthquake record (a strong motion accelerogram) obtained during the damaging 1986 Kalamata earthquake was at its basement. This record is also used for the assessment.

A 220,000-year-long continuous large earthquake record from the central Dead Sea Fault

<p>Large earthquakes (magnitude ≥ 7.0) are rare, especially along slow-slipping plate boundaries. Lack of large earthquakes in the instrumental record enlarges uncertainty of the recurrence time; the recurrence of large earthquakes is generally determined by extrapolation according to a magnitude-frequency relation. We enhance the seismological catalog of the Dead Sea Fault Zone by including a 220,000-year-long continuous large earthquake record based on seismites from the Dead Sea center (ICDP Core 5017-1). We constrain seismic shaking intensities via computational fluid dynamics modeling and invert them for earthquake magnitude. Our analysis shows that the recurrence time of large earthquakes follows a power-law distribution, with a mean of ≤ 1400±160 years. This mean recurrence is significantly shorter than the previous estimate of 11,000 years for the past 40,000 years. Our unique record confirms a clustered earthquake recurrence pattern and a group-fault temporal clustering model, and reveals an unexpectedly high seismicity rate on a slow-slipping plate boundary.</p><p>Our results suggest that researchers may underestimate the seismic hazard potential of similar slow-slipping faults with irregular rupture. Our study highlights the potential of <em>in situ</em> deformed sediment layers in a subaqueous environment as a strong-motion paleo-seismometer to record long seismic sequences covering multiple recurrence intervals of large earthquakes. Long records are vital for accurate hazard assessment. Our quantitative method of seismic record reconstruction, with paleo-earthquake intensity (ground acceleration) and magnitude estimation, may also prove suitable for similar subaqueous environments along other faults.</p>