Seismic Instrumentation Research Articles

Passive Seismology: Lightweight and Rapid Detection of Arctic Subsea and Sub‐Aquatic Permafrost

AbstractLow sea levels during the last Ice Age exposed millions of square kilometers of Arctic shelves which have been subsequently submerged, creating subsea permafrost. In onshore settings, permafrost can also exist beneath water bodies such as coastal lagoons, rivers, and thermokarst lakes. We explored passive seismology as a method for mapping unfrozen sediment thickness above subsea and sub‐aquatic permafrost. We present passive seismic data collected with the Mobile Ocean Bottom Seismic Instrument (MOBSI) from the Beaufort Sea near Tuktoyaktuk in Canada, Ivashkina Lagoon on the Bykovsky Peninsula, as well as a lake and river in the Lena Delta, Siberia, Russia. We use borehole data and frost probe measurements to identify permafrost‐related H/V measurement peaks and calibrate shear wave velocities for frequency‐to‐depth conversion. We employ the shortest path and maximum signal amplitude to connect peaks and generate geological profiles. The MOBSI detected the ice‐bonded permafrost table beneath the Beaufort Sea, as well as beneath a Siberian lake and lagoon. At Tuktoyaktuk, an ocean bottom seismometer revealed a 5% scatter about the peak frequency for three‐minute time windows and over 8 hr of recording time. With peak frequencies ranging from 4.9 ± 0.2 Hz to 27.6 ± 1.4 Hz, the depth to subsea permafrost ranged from 1.4 ± 0.1 m bsl at the shoreline to 14.0 ± 0.4 m bsl 240 m offshore. Given an accurate shear wave velocity, our findings highlight that MOBSI deployment times as short as 3 min are adequate for detecting Arctic subsea and sub‐aquatic permafrost.

Quantifying spatial peat depth with seismic micronodes and the implications for carbon stock estimates

Peatlands are a major store of soil carbon, due to their high concentration of carbon-rich decayed plant material. Consequently, accurate assessment of peat volumes is important for determining land-use carbon budgets, especially in the Northern hemisphere. Determination of carbon stocks at the scale of individual peat sites has principally relied on either mechanical probing or electromagnetic geophysical methods. In this study, we investigated the use of seismic nodal instrumentation for quantifying peat depth. We used Stryde™ nodes for a deployment at the Whixall moss in Shropshire, England. We measured seismic arrival times from peat-bottom reflections, as well as dispersive surface waves to invert for a model of variable peat depth along a linear cross-section. The use of very small seismic nodes (micronodes) allows for particularly rapid deployment on challenging terrain.

Seismic Node Arrays for Enhanced Understanding and Monitoring of Geothermal Systems

Abstract Harnessing geothermal energy will likely play a critical role in reducing global CO2 emissions. However, exploration, development, and monitoring of geothermal systems remain challenging. Here, we explore how recent low-cost seismic node instrumentation advances might enhance geothermal exploration and monitoring. We show the results from 450 nodes deployed at a geothermal prospect in Cornwall, United Kingdom. First, we demonstrate how the nodes can be used to monitor the spatiotemporal and size distribution of induced seismicity. Second, we use focal mechanisms, shear-wave source polarities, and anisotropy to indicate how the dense passive seismic observations might provide enhanced insight into the stress state of the geothermal systems. All the methods are fully automated, essential for processing the data from many receivers. In our example case study, we find that the injection-site fracture orientations significantly differ from that of the crust above and the regional stress state. These observations agree well with fracture orientations inferred from independent well-log data, exemplifying how the nodes can provide new insight for understanding the geothermal systems. Finally, we discuss the limitations of nodes and the role they might play in hybrid seismic monitoring going forward. Overall, our results emphasize the important role that low-cost, easy-to-deploy dense nodal arrays can play in geothermal exploration and operation.

Signal to Noise Ratio Improvement Using Stacking Method on Shallow Refraction Seismic Data

Abstract The improvement of signal-to-noise ratio in refraction seismic survey data is intriguing, especially when a long source-sensor distance and low energy vibration source is in use. In this work, we analyzed the effectiveness of the stacking procedure to extract geophone response signals buried under the noise level. The straight forward strategy to improve the signal quality is by doing multiple acquisition on every offset location and performing stacking procedure on the recorded data. For such activities, the sensor offset location is classified as near-offset (4-26m), middle-offset (28-50m) and far-offset (52-72m). To increase the usefulness of the proposed method, we developed the algorithm using an opensource programming language, and presented it in a step-by-step manner. We presented the procedure accompanied by the pre- and post- processing algorithm, consisting of seismic signal filtering and cross-correlation procedure in order to allow a precise determination of the first break time of the propagated seismic wave. The results give an overview on how to develop a seismic signal processing routine, as well as the possibility to improve the range of the refraction seismic instrumentation systems. The stacking procedure has a high level of significance for the middle offset. For the near offset the stacking procedure is not necessary, whereas for the far offset the large number of data is more important.

Local-S shear wave splitting along the length of the Alaska–Aleutian subduction zone

SUMMARY The Alaska–Aleutian subduction zone represents an ideal location to study dynamics within a mantle wedge. The subduction system spans several thousand kilometres, is characterized by a slab edge, and has ample seismicity. Additionally, the majority of islands along the arc house broad-band seismic instruments. We examine shear wave splitting of local-S phases originating along the length of the subduction zone. We have dense measurement spacing in two regions, the central Aleutians and beneath Alaska. Beneath Alaska, we observe a rotation in fast splitting directions near the edge of the subducting slab. Fast directions change from roughly trench perpendicular away from the slab edge to trench parallel near the boundary. This is indicative of toroidal flow around the edge of the subducting Alaska slab. In the central Aleutians, local-S splitting is primarily oriented parallel to, or oblique to, the strike of the trench. The local-S measurements, however, exhibit a depth dependence where deeper events show more consistently trench-parallel directions indicating prevalent trench-parallel mantle flow. Our local-S shear wave splitting results suggest trench-parallel orientation are likely present along much of the subduction zone excited by the slab edge, but that additional complexities exist along strike.

Using high-precision travel time extraction to detect time deviation of seismic instruments

The method of seismic ambient noise cross-correlations (NCFs) has been demonstrated to be applicable for time offset measurement, especially in evaluating instrument clocks. Continuous recording of seismic ambient noise data makes it possible to analyze the performance of seismic instruments online. However, long-term cross-correlation and stacking calculations are required to obtain accurate travel time from ambient noise, which greatly reduces the time resolution of instrument performance detection. Therefore, we propose a travel time extraction method based on time-frequency analysis, which could obtain the travel time accurately even though the NCF has a low signal-to-noise ratio (SNR), and it is applied to the measurement of clock offsets in seismic instruments. The method combines S Transform and dictionary learning to improve the SNR of NCFs, and uses a peak extraction algorithm based on short-time Fourier transform to obtain accurate travel times. Additionally, the travel time drift of the station pair can be obtained by calculating the travel time difference between causal and acausal parts of NCFs. Using the data from ambient noise observations and the real data with time errors to verify that the proposed method can obtain accurate travel time for NCF with SNR lower than 6 and it can pick up a time offset as low as one sampling point, the detectable change is 0.046% of travel time, which is crucial for detecting weak changes in the performance of seismic instruments.

Electroseismic Scholte‐wave analysis: A potential method for estimating shear‐wave velocity structure of shallow‐water seabed sediments

AbstractThe potential application of conducting Scholte‐wave analysis using electroseismic pressure fields excited by an electric current source due to the electrokinetic effect in fluid‐saturated porous seabed sediments is investigated. First, we develop a numerical modelling algorithm by combining the Luco–Apsel–Chen generalized reflection and transmission method with the peak‐trough averaging method to simulate the electroseismic wave fields in stratified fluid/porous media. The modelling results show that the electroseismic pressure signals recorded on the seafloor are mainly composed of evanescent electroseismic waves, and Scholte waves are the dominant wave pattern. Their amplitudes are generally within the order of magnitudes capable of being detected by current seismic instruments. Then, the modified frequency–Bessel transform method is extended to extract the Scholte‐wave dispersion curves from electroseismic pressure fields. Results demonstrate that Scholte‐wave dispersion curves extracted from electroseismic records are superior to those extracted from conventional seismic wave fields excited by an airgun source under the same source–receiver geometry because they contain many overtones and are almost free from the interferences of dispersive guided waves. Furthermore, the Scholte‐wave dispersion inversion results obtained by employing the Levenberg–Marquardt method show that the shear‐wave velocity model inverted by Scholte‐wave dispersion curves extracted from the electroseismic pressure field is more accurate than those obtained by dispersion curves extracted from the seismic wave fields with the guided‐wave removal. The above results indicate that the electroseismic Scholte‐wave analysis method has the potential to evaluate the shear‐wave velocities of shallow‐water seabed sediments.

Assessment of Sakhalin shelf reservoirs by geomechanical modeling

Background. The complex tectonic structure of the Sea of Okhotsk shelf, its high geodynamic activity and the presence of non-anticlinal traps in plays requires special technologies for studying the secondary filtration-volumetric parameters of reservoirs. The prediction of the location and direction of open fractures is complicated by their small size. Such fractures are frequently too small to be detected by such conventional logging or seismic instruments. The detection of fracturing by seismic methods is impossible in principle; however, some high-resolution logging tools are capable of detecting fractures under favorable circumstances. In cases where neither logging nor seismic exploration can detect fractures, geomechanical modeling can be used. Geomechanical modeling makes it possible to predict the effective porosity and permeability in the сrosshole space.Aim. To assess the geomechanical properties and secondary permeability parameters of the Sakhalin shelf reservoirs.Materials and methods. The ROXAR reservoir modeling software was used to assess the secondary filtration-volumetric parameters of the Sakhalin shelf reservoirs.Results. The modern shear stress field was revealed. The permeability of each stratigraphic horizon was calculated. The filtration capacity of local structures was established.

The measurement and analysis of similarity degree on data from two types of seismic recorders

Seismic instruments are widely used in projects related to geophysical prospecting. Quality data from seismic recorders help to determine subterranean structures with high precision. This paper first introduces a field experiment carried out by deploying seismic stations equipped with two kinds of seismic recorders: GEI (China) and Reftek 130 (USA). Then, the three-component seismograms from GEI are measured and evaluated by comparing with those from Reftek 130 in different aspects: waveforms in time and frequency domain, quantitative analysis by calculation and statistic of correlation coefficient, and signal to noise ratio of seismic signal. Our results were presented by multiple images as the following: (I) Both the time and frequency waveforms of GEI were almost exactly coincident with those of Reftek 130, with over 98.60 percent of the correlation coefficients in the time domain within 0.95–1.0, and all those in the frequency domain above 0.9977. (II) The accurate time lag estimation of GEI’s signal was gained by the lag and correlation algorithms based on left–right sliding windows. The GEI clock was 7.3545 ns behind the Reftek 130 clock after every 1 s, which could be utilized to correct the internal clock to improve the synchronous accuracy of seismic recorders. (III) Some seismic signals from GEI were obviously stronger than those from Reftek 130. Our results may potentially promote and support the optimization of seismic recorders and their application in geophysics methods.

Sensing Optical Fibers for Earthquake Source Characterization Using Raw DAS Records

AbstractDistributed Acoustic Sensing (DAS) is becoming a powerful tool for earthquake monitoring, providing continuous strain‐rate records of seismic events along fiber optic cables. However, the use of standard seismological techniques for earthquake source characterization requires the conversion of data in ground motion quantities. In this study we provide a new formulation for far‐field strain radiation emitted by a seismic rupture, which allows to directly analyze DAS data in their native physical quantity. This formulation naturally accounts for the complex directional sensitivity of the fiber to body waves and to the shallow layering beneath the cable. In this domain, we show that the spectral amplitude of the strain integral is related to the Fourier transform of the source time function, and its modeling allows to determine the source parameters. We demonstrate the validity of the technique on two case‐studies, where source parameters are consistent with estimates from standard seismic instruments in magnitude range 2.0–4.3. When analyzing events from a 1‐month DAS survey in Chile, moment‐corner frequency distribution shows scale invariant stress drop estimates, with an average of Δσ = (0.8 ± 0.6) MPa. Analysis of DAS data acquired in the Southern Apennines shows a dominance of the local attenuation that masks the effective corner frequency of the events. After estimating the local attenuation coefficient, we were able to retrieve the corner frequencies for the largest magnitude events in the catalog. Overall, this approach shows the capability of DAS technology to depict the characteristic scales of seismic sources and the released moment.

Seismic Beacon-A New Instrument for Detection of Changes in Rock Massif.

The seismic beacon is a new instrument that allows for the measurement of changes in a rock massif with high sensitivity. It is based on effects, which affect the propagation of harmonic seismic waves generated continuously with stable and precise frequency and amplitude. These seismic waves are registered by a system of seismic stations. The amplitude of the seismic signal is very small, and it is normally hidden in a seismic noise. Special techniques are applied to increase the signal-to-noise ratio. In 2020, the first prototype of the seismic beacon was constructed in a laboratory, and field tests were performed in 2022 and 2023. During the tests, the changes in spectral amplitude and phase of seismic waves were detected, which is interpreted as the changes in material properties. These measurements testified the basic functionality of the device. The seismic beacon has been developed primarily for the detection of critical stress before an earthquake, which is manifested by non-linear effects such as higher harmonics generation. In addition, it could be used, for example, in the detection of magma movements, groundwater level changes, changes in hydrocarbon saturation in rocks during the extraction of oil and natural gas, or the penetration of gases and liquids into the earth's crust.

Active‐Source Seismic Imaging of Fault Re‐Activation and Leakage: An Injection Experiment at the Mt Terri Rock Laboratory, Switzerland

AbstractWe conducted a time‐lapse seismic experiment utilizing automated active seismic source and sensor arrays to monitor a reactivated fault within the Opalinus clay formation at the Mont Terri Rock Laboratory (Switzerland), an analog caprock for geologic carbon storage. A series of six brine injections were conducted into the so‐called Main Fault to reactivate it. Seismic instrumentation in five monitoring boreholes on either side of the fault was used to continuously probe changes in P‐wave travel‐times associated with fault displacement and leakage. We performed time‐lapse travel‐time tomography on five hundred sequential data sets; this revealed a zone of decreased P‐wave velocity, up to 16 m/s, during each injection cycle, followed by a velocity increase during shut‐in. These results demonstrate varying elastic property perturbations, both spatially and temporally, along the fault plane during reactivation. We then interpreted these velocity changes in terms of fault dilation induced by pressurized fluids along the fault.

Analysis of the Influence of Burden Deviation from the Designed One on the Intensity of the Blast Vibration

This paper presents an analysis of the influence of burden deviation from the designed one on the intensity of blasting vibrations through the use of laboratory and field examinations. By definition, the burden represents the shortest distance from the axis of an explosive column charge to the free surface. It should be measured along the entire hole length, although, in practice, it is often measured only on the bench surface as the shortest distance from the axis of the explosive column charge to the crest. The real surface of the bench slope (free face) can be very irregular and should be considered during every blast. The deviation of burden in the blast pattern represents a serious problem in the field during blasting operation. Burden deviation from the designed one can be greater or lesser, affecting the results of blasting through poor fragmentation and sometimes causes unwanted effects like increased blasting vibrations or fly rock. The influence of burden deviation on the intensity of blasting vibrations was tested on a laboratory model, where 8 mm diameter holes were drilled into blocks with certain dimensions. The small explosive charges placed in blastholes were initiated. The design burden was set at 30 mm, as the distance from blastholes to the free face of the blocks. Any deviation in distance greater than the designed burden was taken as a parameter for comparison. During each initiation, vibrations were measured using a seismic instrument at a distance of 150 mm from the borehole. At the same time, the free face in the front of the blastholes was photographed to create a detailed 3D model of the blasted surface of the blocks for each blasting. Each measurement is presented on a diagram and classified depending on the values of the burden in the cases where the value of the burden is equal to the designed one, as well as any deviation that is smaller or larger than 30 mm. A total of 55 tests were carried out. The results were analyzed, and the model of dependence of each burden deviation from the designed one on the intensity of blasting vibrations was established under laboratory conditions. To verify the model, the same experiments were also applied in the field. The basic parameter of the model, the coefficient K, which represents the ratio of peak particle velocity and the surfaces of the blasted material from laboratory and field testing, indicates that there is a connection between these values. The deviation of the coefficient K, obtained from laboratory and field measurements, was 5.5%.

Development of the Site Characterization Database for the 2022 New Zealand National Seismic Hazard Model

Abstract This article presents the development of the site characterization database for the 2022 New Zealand National Seismic Hazard Model update. This database summarizes the site characterization parameters at past and present GeoNet seismic monitoring network instrument locations, including strong-motion, short-period, and broadband seismometer stations. Site characterization parameters required to assess and improve empirical ground-motion models and those used in codified seismic design frameworks internationally have been included in the database. Measurement uncertainty was assigned, and the quality of the data used to assign each parameter was classified. The site period (T0) was the most well constrained of all the site parameters, with almost half of the database classified based on high-quality measurements, with these dominated by microtremor-based horizontal-to-vertical spectral ratio. Although there was an improvement in the quality of the parameters representing the time-averaged shear-wave velocity in the uppermost 30 m of the profile (VS30), little site-specific data were available, with almost no information for rock sites. Most of these classifications were based on national maps or geologic interpretation. Depth-based parameters (Z1.0 and Z2.5) had the lowest quality overall, with very few direct measurements available to constrain these values. Despite these limitations, the quality of parameters assigned to instrument locations has improved and greatly expanded previous databases through the assignment of parameter values to the entire GeoNet seismic network.

Bayesian analysis of ground motion models using chimney fragility curves: 2021, 5.9-Mw Woods Point intraplate earthquake, Victoria, Australia

The 22 September 2021 (AEST) MW 5.9 Woods Point earthquake occurred in an intraplate setting (southeast Australia) approximately 130 km East Northeast of the central business district of Melbourne (pop. ∼5.15 million). A lack of seismic instrumentation and a low population density in the epicentral region resulted in a dearth of near-source instrumental and “felt” report intensity data, limiting evaluation of the near-source performance of ground motion models (GMMs). To address this challenge, we first surveyed unreinforced masonry chimneys following the earthquake to establish damage states and develop fragility curves. Using Bayesian inference, and including pre-earthquake GMM weightings as Bayesian priors, we evaluate the relative performance of GMMs in predicting chimney observations for different fragility functions and seismic velocity profiles. At the most likely VS30 (760 m/s), the best performing models are AB06, A12, and CY08SWISS. GMMs that were preferentially selected for utility in the Australian National Seismic Hazard Model (NSHA18) prior to the Woods Point earthquake outperform other GMMs. The recently developed NGA-East GMM performs relatively well in the more distal region (e.g. >50 km) but is among the poorest performing GMMs in the near-source region across the range of VS30. Our new method of combining analysis of engineered features (chimneys) with Bayesian inference to evaluate the near-source performance of GMMs may have applicability in diverse settings worldwide, particularly in areas of sparse seismic instrumentation.

Recent seismicity on the Kerguelen islands

The Kerguelen archipelago, one of the largest oceanic archipelagos in the world, was built by an active hotspot interacting with a ridge between 110 and 40 million years ago; since then, the ridge has migrated over 1000~km away and the archipelago's volcanic activity has been steadily decreasing. Despite the lack of recent active tectonics and the quiescent volcanism of the Kerguelen archipelago, there have been several observations of seismic events of unknown origin in its vicinity. The only seismic instrument within 1000~km of the archipelago was installed on Kerguelen's main island in the 1980's. In this study we apply modern earthquake detection techniques to the continuous waveforms recorded by this seismometer over the past 20 years. We reveal that the Kerguelen archipelago islands hosts an abundant seismicity. This seismicity exhibits swarm-like characteristics in several clusters while at other locations the earthquakes appear more steady over time. We locate most events near the largest icecap of the main island. We speculate that the origin of the earthquakes can be linked to residual volcanic, magmatic, or hydrothermal activity at depth, all of which can be favored by flexural stress caused by the documented fast retreat of icecap. This seismicity may also indicate that the Kerguelen hotspot shows signs of unrest.

Optimal Network Design for Microseismic Monitoring in Urban Areas - A Case Study in Munich, Germany

Well-designed monitoring networks are crucial for obtaining precise locations, magnitudes and source parameters, both for natural and induced microearthqakes. The performance of a seismic network depends on many factors, including network geometry, signal-to-noise ratio (SNR) at the seismic station, instrumentation and sampling rate. Therefore, designing a high-quality monitoring network in an urban environment is challenging due to the high level of anthropogenic noise and dense building infrastructure, which can impose geometrical limitations and elevated construction costs for sensor siting. To address these challenges, we apply a numerical optimization approach to design a microseismic surveillance network for induced earthquakes in the metropolitan area of Munich (Germany), where several geothermal plants exploit a deep hydrothermal reservoir. First of all, we develop a detailed noise model for the city of Munich, to capture the heterogeneous noise conditions. Then, we calculate the expected location precision for a randomly chosen network geometry from the body-wave amplitudes and travel times of a synthetic earthquake catalog considering the modeled local noise level at each network station. In the next step, to find the optimum network configuration, we use a simulated annealing approach in order to minimize the error ellipsoid volume of the linearized earthquake location problem. The results indicate that a surface station network cannot reach the required location precision (0.5 km in epicentre and 2 km in source depth) and detection capability (magnitude of completeness Mc = 1.0) due to the city´s high seismic noise level. In order to reach this goal, borehole stations need to be added to increase the SNR of the microearthquake recordings, the accuracy of their body-wave arrival times and source parameters. The findings help to better quantify the seismic monitoring requirements for a save operation of deep geothermal projects in urban areas.

Wavefield Modeling and Analysis of Lightning Quakes Measured by a Distributed Acoustic Sensing Array

ABSTRACT Lightning-induced seismic waves, termed “lightning quakes,” are frequent natural sources in many storm-prone regions. Lightning quakes have been clearly observed in numerous environments by both seismic and acoustic instruments, for example, by distributed acoustic sensing (DAS) array. Despite these numerous observations, the physical nature of lightning quake wavefields detected by ground-based arrays remains poorly understood. The possibility of electroseismic (ES) conversion due to lightning’s powerful electromagnetic fields was, until now, unstudied. This investigation uses 3D numerical simulations of acoustic-to-seismic and ES wavefields alongside a novel data-driven azimuthal strain-rate variation analysis technique to robustly reveal the complex nature of lightning quakes. We show that lightning quakes begin as airborne acoustic waves before coupling with the solid earth as air-coupled Rayleigh waves and Love waves that are generated by local sources near the receiver, such as topography or urban infrastructure. These conclusions suggest thunder observations from a DAS array can be used to infer the structure of the near surface around the receiver, but care needs to be taken in understanding the role of local sources. An estimate of the Rayleigh- and Love-wave phase velocities is produced using a novel data analysis method unique to DAS. Furthermore, we demonstrate that electroseismic coupling does not play a significant role in the lightning quake wavefields. Although these simulations do not fully capture the realistic frequency of the electroseismic coupled wavefield, theory suggests that the wavefield is high frequency and thus quickly attenuated in the saturated near-surface soils. Electroseismic coupled wavefields from lightning may be detectable very close to the bolt.

Analysis of Regional Ambient Seismic Noise in the Chukchi Sea Area in the Arctic Based on OBS Data from the Ninth Chinese National Arctic Scientific Survey

Ambient noise plays a crucial role in influencing the observation quality at seismic stations. By studying the distribution patterns of ambient noise, we can gain initial insights into the noise conditions within a specific research area. This paper investigates the properties of ambient noise in different frequency bands under environmental settings in the Chukchi Sea region, utilizing data collected from ocean bottom seismometers (OBSs) deployed during the Ninth Chinese National Arctic Scientific Survey. The probability density function (PDF) method is used to reveal the distinctive features of ambient noise. In addition, by comparing the crowed number values of ambient noise in the Chukchi Sea area with the global new low-noise model (NLNM) and new high-noise model (NHNM), a more comprehensive understanding of the patterns, distribution characteristics, and sources of ambient noise in the Arctic Chukchi Sea area is gained. The study suggests that the overlying sea ice in the Arctic Chukchi Sea area can suppress the microseismic band ambient noise, and the overall level of ambient noise in the Chukchi Sea area lies between the land seismic ambient noise level and the ambient noise level in the middle- and low-latitude sea areas. Meanwhile, an abnormal power spectrum caused by different levels of natural earthquakes is observed. This study fills the gap by using seafloor seismic instruments to investigate ambient noise in the Chukchi Sea area.

Development of recommendations for the implementation of seismic risk mitigation policy in the Russian Federation based on world experience

The current state of practice of seismic risk mitigation policy in the following countries is analyzed: Japan, USA, China, Italy and the Russian Federation. In particular, the paper compares seismic retrofit policies for existing buildings and financing mechanisms for comprehensive seismic risk mitigation in the context of each country's regulatory framework. The analysis of the current seismic risk mitigation policy in the Russian Federation leads to the conclusion that it needs serious modernization and reorganization, including: 1) development of a new generation of standards specifying nonlinear analysis methods and 2) development of effective financing mechanisms for the seismic evaluation and seismic modernization of the existing building stock. 
 The aim of this paper is to identify best practices in seismic retrofitting policy that may be useful for the implementation and adjustment of seismic risk mitigation policies in the Russian Federation at the federal and regional levels. 
 The result of the paper is a set of recommendations based on the most effective seismic risk mitigation policy instruments, grouped according to the key stages of the seismic amplification process:
 – risk assessment of existing buildings;
 – knowledge transfer; 
 – setting targets for the seismic modernization; 
 – implementation of the seismic strengthening policy;
 – policy implementation monitoring.