Erdinc Saygin

• PhD
• Senior Researcher at The Commonwealth Scientific and Industrial Research Organisation

Seismic full waveform inversion (FWI) has become a popular tool for estimating subsurface models using both the amplitude and phase of seismograms. Unlike the conventional gradient-based approach, Bayesian inference using Markov chain Monte Carlo (MCMC) sampling can remove dependence on starting models and can quantify uncertainty. We have develope...

We retrieve the local P wave empirical Green's functions between the elements of five different regional arrays across the globe by cross‐correlating and bin stacking the teleseismic earthquake coda waves recorded at each array. The stack is made using the coda of P and S wave phases for events in the distance range from 40° to 50° from the center...

Imaging using information derived from the cross-correlation of the ambient seismic wavefield at different stations has recently become an important tool in seismology. We here present a continent wide study of the Australian crust based on the exploitation of continuous data from extensive portable broad-band deployments across Australia and the p...

The autocorrelation of the seismic transmission response of a layered medium (autocorrelogram), in the presence of a free surface, corresponds to the reflection response. Despite many studies on the imaging of local structures through retrieval and forward modeling of stacked autocorrelograms, there is limited work on the inversion of these data. I...

We autocorrelate the continuously recorded seismic wavefield across a dense network of seismometers to map the P-wave reflectivity response of the Jakarta Basin, Indonesia. The proximity of this megacity to known active faults and the subduction of the Australian plate, especially when the predominance of masonry construction and thick sedimentary...

Distributed acoustic sensing (DAS) records represent the strain (rate) in an optical fiber averaged over a gauge length about a specified channel. In the presence of bends and variable coupling to the surroundings, the effect of gauge-length averaging is more complex than for a straight cable. Analysis for an incident plane wavefront shows how both...

We use seismic ambient noise recorded by dense ocean bottom nodes (OBNs) in the Gorgon gas field, Western Australia, to compute time‐lapse seafloor models of shear‐wave velocity. The extracted hourly cross‐correlation (CC) functions in the frequency band 0.1–1 Hz contain mainly Scholte waves with very high signal‐to‐noise ratio. We observe temporal...

We use seismic ambient noise recorded by dense ocean bottom nodes (OBNs) in the Gorgon gas field, Western Australia, to compute time-lapse seafloor models of shear-wave velocity. The extracted hourly cross-correlation (CC) functions in the frequency band 0.1 – 1 Hz contain mainly Scholte waves with very high signal to noise ratio. We observe tempor...

The proliferation of seismic networks in Australia has laid the groundwork for high-resolution probing of the continental crust. Here we develop an updated 3D shear-velocity model using a large dataset containing nearly 30 years of seismic recordings from over 1600 stations. A recently-developed ambient noise imaging workflow enables improved data...

Türkiye poses a complex crustal structure and tectonic settings owing to the northward convergence of the Arabian and African plates with respect to the Anatolian and Eurasian plates. A reliable 3-D crustal structure of the unruptured segment of the North Anatolian Fault Zone (NAFZ) in the Sea of Marmara is thus of utmost importance for seismic haz...

Ambient noise seismic data are widely used by geophysicists to explore subsurface properties at crustal and exploration scales. Two‐step dispersion inversion schema is the dominant method used to invert the surface wave data generated by the cross‐correlation of ambient noise signals. However, the two‐step methods have a 1‐D layered model assumptio...

Seismic noise poses challenges for gravitational wave detection. Effective vibration isolation and methods to subtract unshieldable Newtonian noise are examples. Seismic arrays offer one way to deal with these issues by making use of correlations between seismic ground measurements and noise inside the detector. In this paper we find that wind indu...

Oceanic crust forms at mid-ocean spreading centres through a combination of magmatic and tectonic processes, with the magmatic processes creating two distinct layers: the upper and the lower crust. While the upper crust is known to form from lava flows and basaltic dykes based on geophysical and drilling results, the formation of the gabbroic lower...

Plain Language Summary Geological carbon storage is one of the key technologies for reducing the greenhouse gas effects. The storage projects may reactivate subsurface faults and lead to felt earthquakes and even surface deformations. We present a new case study, Stage 2C of the CO2CRC Otway Project (Victoria, Australia), where a small leakage‐like...

Constraints on crustal and uppermost mantle structure provide key information for understanding the geodynamic processes that have shaped the geological expressions and are currently causing deformation in Anatolia. We apply a novel method of Bayesian inversion of autocorrelated teleseismic P‐wave coda data to retrieve the crustal and uppermost man...

Newtonian machine learning (NML) is a wave-equation inversion method that inverts single-dimensional latent space (LS) features of the seismic data for retrieving the subsurface background velocity model. The single-dimensional LS features mainly contain the kinematic information of the seismic data, which are automatically extracted from the seism...

Distributed acoustic sensing (DAS) provides an alternative and cost-efficient solution for recording seismic waves with high acquisition density (meter-scale), with emerging applications in ambient-noise, active-source, and earthquake seismology. Here we deployed DAS of fiber-optic cable vertically in a borehole of approximately 340 m depth at the...

Traditional approaches of using dispersion curves for S-wave velocity reconstruction have limitations, principally, the 1D-layered model assumption and the automatic/manual picking of dispersion curves. At the same time, conventional full-waveform inversion (FWI) can easily converge to a non-global minimum when applied directly to complicated surfa...

The sensitivity of seismic compressional and shear waves and their velocity ratios to rock lithology, pore fluids, and high‐temperature materials makes these parameters very useful for constraining the physical state of the crust. In this study, we develop a joint inversion approach utilizing both radial and vertical components’ autocorrelations of...

We present a hybrid machine learning (HML) inversion method, which uses the latent space (LS) features of a convolutional autoencoder (CAE) to estimate the subsurface velocity model. The LS features are the effective low‐dimensional representation of the high‐dimensional seismic data. However, no equations exist to describe the relationship between...

Oceanic crust is formed at mid-ocean spreading centres by a combination of magmatic, tectonic and hydrothermal processes. The crust formed by magmatic process consists of an upper crust generally composed of basaltic dikes and lava flows and a lower crust presumed to mainly contain homogeneous gabbro whereas that by tectonic process can be very het...

Seismic full waveform inversion (FWI) is a powerful method for estimating quantitative subsurface physical parameters from seismic data. As the full waveform inversion is a non-linear problem, the linearized approach updates model iteratively from an initial model, which can get trapped in local minima. In the presence of a high velocity contrast,...

We present a new seismic inversion method which uses the deep learning (DL) features for the subsurface velocity model estimation. The DL feature is a low-dimensional representation of the high-dimensional seismic data, which is automatically generated by a convo-lutional autoencoder (CAE) and preserved in the latent space. The low-dimensional DL f...

Seismic body‐wave tomography studies typically assume an isotropic upper mantle, possibly mapping anisotropy into artificial isotropic velocity anomalies in the resulting images. The Eastern Mediterranean with its oceanic, continental, and extinct subduction systems, as well as dense station coverage, provides an ideal setting to explore this issue...

A controlled-release test at the In-Situ Laboratory Project in Western Australia injected 38 tonnes of gaseous CO2 between 336−342 m depth in a fault zone, and the gas was monitored by a wide range of downhole and surface monitoring technologies. Injection of CO2 at this depth fills the gap between shallow release (<25 m) and storage (>600 m) field...

The Late Cretaceous kimberlites in northern Alberta, Canada, intruded into the Paleoproterozoic crust and represent a nonconventional setting for the discovery of diamonds. Here, we examined the origin of kimberlite magmatism using a multidisciplinary approach. A new teleseismic survey reveals a low-velocity (–1%) corridor that connects two deep-ro...

Upper mantle dynamics (e.g. subduction processes, slab roll-back, slab tearing and mantle upwelling) impact eastern Mediterranean region tectonics but a detailed understanding of the acting forces has remained elusive. Further progress requires more accurate measurements not just of the surface kinematics (from GPS) but also of indirect indicators...

Seismic full waveform inversion (FWI) is a state-of-the-art technique for estimating sub-surface physical models from recorded seismic waveform, but its application requires care because of high non-linearity and non-uniqueness. The final outcome of global convergence from conventional FWI using local gradient information relies on an informative s...

Empirical Green's function (EGF) retrieval commonly relies on cross‐correlating the long‐term ambient seismic wavefield that is simultaneously recorded at multiple stations. Recent studies have demonstrated observationally that cross‐correlating the coda of ambient noise cross‐correlation functions enables reconstruction of the EGFs, regardless of...

In order to explore the effects of environmental subsurface changes on seismic velocities, we use nearly four years (2015-2018) of continuous ambient seismic noise data recorded in a multi-level borehole to measure relative seismic surface wave velocity changes at the SW Hub CO2 Geosequestration Site using seismic noise interferometry. We find a di...

S U M M A R Y We investigated the seismic shear wave velocity structure of the upper crust beneath the Ban-dung area in West Java, Indonesia, using ambient seismic noise tomography. We installed 60 seismographs to record ambient seismic noise continuously in the city of Bandung and its surrounding area for 8 months. After interstation cross-correla...

S U M M A R Y We investigated the seismic shear wave velocity structure of the upper crust beneath the Ban-dung area in West Java, Indonesia, using ambient seismic noise tomography. We installed 60 seismographs to record ambient seismic noise continuously in the city of Bandung and its surrounding area for 8 months. After interstation cross-correla...

The autocorrelation of the seismic transmission response of a layered medium (autocorrelogram), in the presence of a free surface, corresponds to the reflection response. Despite many studies on the imaging of local structures through retrieval and forward modelling of stacked autocorrelograms, there is limited work on the inversion of these data....

Seismic interferometry, commonly known as empirical Green’s function retrieval in seismology, has been widely applied to extract the impulse response of Earth. The conventional approach based on cross-correlation of long-term ambient seismic wavefield relies on the simultaneous recording of noise signals at seismic receivers. Recent studies have de...

Having knowledge of 3-D high-resolution physical properties for the crustal structure along the North Anatolian Fault Zone (NAFZ) in NW Turkey will greatly contribute to future seismic hazard scenarios, which will be developed for a region including the Sea of Marmara. In this study, we provide the first detailed shear wave velocity structure of NW...

Empirical Green's function (EGF) retrieval commonly relies on cross-correlating the long-term ambient seismic wavefield that is simultaneously recorded at multiple stations. Recent studies have demonstrated observationally that cross-correlating the coda of ambient noise cross-correlation functions (C3) enables reconstruction of the EGFs, regardles...

Seismic full waveform inversion (FWI) has become a popular tool for estimating subsurface models using both the amplitude and phase of seismograms. Unlike the conventional gradient-based approach, Bayesian inference using Markov chain Monte Carlo (MCMC) sampling can remove dependence on starting models and can quantify uncertainty. We have develope...

Iranian Seismological Center (IRSC) and International Institute of Earthquake Engineering and Seismology (IIEES) networks. Empirical Green's functions between the vertical components of the station pairs are reconstructed by cross-correlating the seismic noise (C 1) and recorrelating the coda of the noise-correlations (C 3). The combination of thes...

Global compilation of seismic anisotropy measurements and models (e.g. from SKS splitting, surface waves to-mography, receiver functions analyses, etc.) suggest that anisotropy is present in most subduction zones. Despite this fact, seismic tomography studies usually consider an isotropic upper mantle. In the present work, we gather seismological a...

Bandung is located on a thick sedimentary basin, which is mainly composed of volcanic rocks and the depositional remnants of an ancient lake. The high population density and vital infrastructure, surrounding by potential sources of earthquakes make Bandung vulnerable to earthquake impact. To study the seismic response of Bandung, a microzonation st...

Characterizing the interior structure of the Jakarta Basin, Indonesia, is important for the improvement of seismic hazard assessment there. A dense-portable seismic broad-band network, comprising 96 stations, has been operated between October 2013 and February 2014 covering the city of Jakarta. The seismic network sampled broad-band seismic noise m...

We present a general concept for evolutionary, collaborative, multiscale inversion of geophysical data, specifically applied to the construction of a first-generation Collaborative Seismic Earth Model. This is intended to address the limited resources of individual researchers and the often limited use of previously accumulated knowledge. Model evo...

Global compilation of seismic anisotropy measurements and models (e.g. from SKS splitting, surface waves to-mography, receiver functions analyses, etc.) suggest that it is present in most subduction zones. Despite this fact, seismic tomography studies usually assume an isotropic upper mantle. In the present work, we gather seismolog-ical and 3D num...

The characteristics of internal lithospheric discontinuities carry crucial information regarding the origin and evolution of the lithosphere. However, the formation and mechanisms of the mid-lithosphere discontinuity (MLD) are still enigmatic and controversial. We investigate the mid-lithospheric discontinuities beneath the Archean Western Australi...

The complex geological structures in East Java and Bali provide important opportunities for natural resource exploitation, but also harbor perils associated with natural disasters. Such a condition makes the East Java region an important area for exploration of the subsurface seismic wave velocity structure, especially in its upper crust. We employ...

Yogyakarta is part of central Java region that closed to Merapi volcano one of famous active volcano in Indonesia. On May 27, 2006 at 5.54 AM local time, a Mw 6.3 earthquake occurred in southern Java Island, Indonesia, about 20 km from Yogyakarta. In our previous study, We applied cross correlation of the ambient seismic noise using data from the M...

IDENTIFICATION OF THE EXISTENCES OF THE MUD VOLCANOES BENEATH EAST JAVA-INDONESIA REGION USING AMBIENT NOISE TOMOGRAPHY

We analyze seismic ambient noise data recorded at a set of permanent and temporary stations across southeastern Tibet to image crustal structure. High-resolution phase velocity maps are presented based on Transdimensional Bayesian Seismic Ambient Noise Tomography. Seismic images exhibit more apparent horizontal heterogeneities and show more detaile...

Bandung is one of the most densely populated cities in Indonesia with vital infrastructures. On the other hand, this area is surrounded by potential sources of earthquakes that make Bandung vulnerable to earthquakes. Structure of seismic velocity and sediment thickness are crucially needed in the earthquake hazard reduction program for Bandung. Bas...

The complexity of geology structure in eastern Java causes this region has many potential resources as much as the disasters. Therefore, the East Java province represents an interesting area to be explored, especially regarding its upper crustal structure. To investigate this structure, we employ the Ambient Noise Tomography (ANT) method. We have u...

In our previous studies, P- and S-wave velocity structures beneath the Sunda Arc were successfully imaged using a global data set and a nested regional-global tomographic method was employed. To obtain more detailed P- and S-wave velocity structures beneath Java, in the central part of the Sunda Arc, we then used local data sets, i.e. newline from...

In order to characterize the subsurface structure of the Jakarta Basin, Indonesia, a dense portable seismic broad-band network was operated by The Australian National University (ANU) and the Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG) between October 2013 and February 2014. Overall 96 locations were sampled through success...

East Java is a part of the Indonesian archipelago that experiences a high level of seismic and volcanic activity, which is either directly or indirectly related to the northward subduction of the Australian plate off Java’s southern coast. Recent geological and volcanic events that have occurred in this region include the LUSI mud volcano eruption...

Current estimates of Moho depth in southeastern Australia are based on sparse sampling. The results are augmented with 180 new Moho estimates constructed from spatial stacks of crustal P wave reflectivity derived from autocorrelograms at over 750 stations. The spatial stacks of reflectivity are constructed using a Gaussian with half-width 0.5°. Pic...

Deep seismic reflection profiling confirms that the Paleo- to Mesoproterozoic Mount Isa mineral province comprises three vertically stacked and partially inverted sedimentary basins preserving a record of intracontinental rifting followed by passive margin formation. Passive margin conditions were established no later than 1655. Ma before being int...

East Java has a fairly complex geological structure. Physiographically East Java can be divided into three zones, i.e. the Southern Mountains zone in the southern part, the Kendeng zone in the middle part, and the Rembang zone in the northern part. Most of the seismic hazards in this region are due to processes in the upper crust. In this study, th...

The geological features of the central Java region, Indonesia, is strongly heterogeneus due to it history of active tectonics and volcanic activity. We cross-correlated the ambient seismic noise using data over 100 broadband and shortperiod seismic stations from Merapi Amphibious Experiment (MERAMEX) and applied a fully nonlinear 2D Bayesian probab...

Our previous study on MERAMEX data (Zulfakriza et al., 2014) obtained features of the tomographic images which correlate well with the surface geology of central Java in periods between 1 to 12 sec. Kendeng Basin and active volcanoes in the central part of this region are clearly imaged with low group velocities with values around 0.8 km/sec, while...

The transition between the crust and mantle across the Australian continent shows considerable variations in both depth and sharpness. Recent extensive seismic reflection profiling provides a comprehensive data set to investigate the nature of the Moho in a wide range of geological environments. In reflection seismology the crust is normally charac...

This paper reports geophysical anomalies and intra-crystalline quartz lamellae in drill cores from the Warburton West Basin overlapping the border of South Australia and the Northern Territory. The pre-Upper Carboniferous ~ 450x300 km-large Warburton Basin, north-eastern South Australia, is marked by distinct eastern and western magnetic, gravity a...

Ambient noise tomography is relatively a new method for imaging the shallow structure of the Earth subsurface. We presents the application of this method to produce a Rayleigh wave group velocity maps around the Merapi Volcano, Central Java. Rayleigh waves group velocity maps were reconstructed from the cross-correlation of ambient noise recorded b...

The subsurface structure of Merapi volcano is crucial to understand to quantify the risk of eruption. The 2010 massive eruption indicates that Merapi is one of the most active and hazardous volcanoes in the world. Previous studies of Merapi have been carried out by numerous research groups, particularly by employing seismo-volcanological methods. D...

The subsurface structure of Merapi volcano is crucial to understand to quantify the risk of eruption. The 2010 massive eruption indicates that Merapi is one of the most active and hazardous volcanoes in the world. Previous studies of Merapi have been carried out by numerous research groups, particularly by employing seismo-volcanological methods. D...

The subsurface structure of Merapi volcano is crucial to understand to quantify the risk of eruption. The 2010 massive eruption indicates that Merapi is one of the most active and hazardous volcanoes in the world. Previous studies of Merapi have been carried out by numerous research groups, particularly by employing seismo-volcanological methods. D...

The geological features of the central Java region, Indonesia, is strongly heterogeneous due to it history of active tectonics and volcanic activity. We have successfully cross-correlated the ambient seismic noise using data from the MERapi AMphibious EXperiment (MERAMEX) and applied a fully nonlinear 2-D Bayesian probabilistic inversion technique...

Delineating the crustal structure of central Java is crucial for understanding its complex tectonic setting. How ever, seismic imaging of the strong heterogeneity typical of such a tectonically active region can be challenging, particularly in the upper crust where velocity contrasts are strongest and steep body wave ray-paths provide poor resoluti...

Geological structure in the region of central Java is very important for understanding its tectonic setting. The presence of several active volcanoes such as Mt. Merapi, Mt. Sumbing and Mt. Lawu, as well as the Kendeng Basin and Opak fault all contribute to the complex geology of central Java. Understanding some of the characteristics of the geolog...

Delineating the crustal structure of central Java is crucial for understanding its complex tectonic setting. However, seismic imaging of the strong heterogeneity typical of such a tectonically active region can be challenging, particularly in the upper crust where velocity contrasts are strongest and steep body wave ray paths provide poor resolutio...

We use seismic tomography, exploiting group velocities derived from ambient noise, to delineate the crustal structure beneath Mt Isa and the surrounding blocks and basins. The depth extent of the blocks can be traced into the mid-crust and the spatial extent of the associated velocity anomalies mapped over an area of approximately 500 km by 500 km....

Delineating the upper crustal structures beneath Yogyakarta is necessary for understanding its tectonic setting. The presence of Mt. Merapi, fault line and the alluvial deposits contributes to the complex geology of Yogyakarta. Recently, ambient seismic noise tomography can be used to image the subsurface structure. The cross correlations of ambi...

Available for Free download (approx 122 Mb) from: http://press.anu.edu.au/titles/deep-crustal-seismic-reflection-profiling

Multi-scale full waveform inversion of complete continental- and regional-scale seismograms reveals the crustal and upper-mantle signature of the North Anatolian Fault Zone which shapes the neotectonics of Turkey and the eastern Mediterranean. Within the crust, the fault zone is mostly bounded by several high-velocity blocks, suggesting that it dev...

We develop and apply a full waveform inversion method that incorporates seismic data on a wide range of spatio-temporal scales, thereby constraining the details of both crustal and upper-mantle structure. This is intended to further our understanding of crust-mantle interactions that shape the nature of plate tectonics, and to be a step towards imp...

We applied cross correlation of the ambient seismic noise using data from the MERapi AMphibious EXperiment (MERAMEX) to tomographic imaging of upper crustal structures in Central Java, Indonesia. The data were collected for about 150 days from May to October 2004 with 134 stations of a temporary seismological network. More than 8000 Rayleigh wave G...

We present the first-generation seismic model of the crust and upper mantle beneath Europe and western Asia, constrained by the full waveform inversion of complete teleseismic and regional seismograms in a broad period range (8-200 s). Our method combines the spectral-element modelling of seismic wave propagation, adjoint techniques and the quantif...

Here we present first-order results detailing the Anatolian crustal from receiver function analysis of data from approximately 300 stations within Turkey. Seismic data from the Kandilli Observatory array (KOERI; KO), the National Seismic Network of Turkey (AFAD-DAD; TU) and available IRIS data from the Northern Anatolian Fault experiment (YL) for t...

The Eastern Warburton Basin, Northeast South Australia, features major geophysical anomalies, including a magnetic high of near-200 nT centred on a ~ 25 km-wide magnetic low (< 100 nT), interpreted in terms of a magmatic body below 6 km depth. A distinct seismic tomographic low velocity anomaly may reflect its thick (9.5 km) sedimentary section, hi...

Stations on the Australian continent receive a rich mixture of continuous ground motion with ambient seismic noise from the surrounding oceans, and numerous small earthquakes in the earthquake belts to the north in Indonesia, and east in Tonga-Kermadec, as well as more distant source zones. The ground motion at a seismic station contains informatio...