Detection and imaging of faults and other subsurface structures in urban settings
Institute of Geophysical and Geochemical Exploration (IGGE) of CAGS successfully performed a high density 2D and 3D combined survey in sub-center of Beijing in September, 2018, to get a high-resolution subsurface images and fault structures.
SmartSolo node seismic system is employed to minimize the impact on the environment and the local population. The subsurface fault structure in depth can be identified from the stacking profile.
|Survey area||483 m × 400 m|
|Target||Fault detection (target depth: 600 m)|
|Survey||2D + 3D High density seismic array|
|Channel count||IGU-16 1C 5-Hz, 700 channels|
|Source||Vibroseis,1600 VPs, sweep 10-130Hz, 12 s|
|Receiver interval||5 m|
|Source interval||10 m|
Google Earth image of the survey area. The shot line is in red, and the color gradient indicates the fold density. (Shuiyu Luo, IGGE, 2018)
Geoscience Australia national geological survey
Geoscience Australia successfully completed a national Geological survey project (OSMT), to detect the deep crustal structures up to the depth of Moho interface through reflection profiling in 2017. The main object is to study the geodynamic evolution, assess mineral potential, and map natural hazard zones. The detailed information can be found at
|Location||South Lachlan, Australia|
|Survey line||600 km|
|Target||Deep structure detection|
|Channel count||IGU-16 1C 10 Hz, 5000 channels|
|Source||Vibroseis, 24s sweep (20+ s listen), 4-96Hz|
|Receiver interval||10 m|
|Source interval||40 m|
Australian natural gas exploration based on compressive sensing imaging (CSI)
SmartSolo is carrying out a practical exploration project in Australia based on compressed sensing technology, which is a popular research topic at present. SmartSolo nodal system is light, simple, and highly reliable. It is very suitable for being deployed in non-uniform spacing when the signal is processed using compressed sensing method. The production efficiency and HSE level are both improved.
|Survey area||About 300 sq km|
|Target||Natural gas detection|
|Channel count||IGU-16 1C 5Hz, 20000 chs|
|Receiver interval||Nominal 40m|
|Source interval||Nominal 10m|
Random receiver spacing in line
Pseudo-reflection profile through correlation of ambient noise
China University of Geoscience, Beijing, conducted a research on application of ambient noise imaging in August, 2018. This study attempts to apply the noise data to detect the shallow urban subsurface structure. Following result is from professor Lanbo Liu, 2018. As the result, correlation between first channel and all channels of the line and by correlation between two neighbor channels are very clear.
|Survey line||600 m|
|Channel count||IGU-16 5 Hz, 200 channels|
|Receiver interval||3 m|
(Note: I replaced the old one by a more accurate setup of the array –Lanbo Liu)
Map view of fault strike (red line) and two survey lines (white line) along the road
S wave velocity inversion through Rayleigh wave dispersive curve
In June, 2018, Researchers from Jilin University got the S wave velocity from Rayleigh wave dispersive curve with 2 hours’ observation data, acquired by 10 IGU-16 1C (5 Hz) stations. The velocity curve is consistent with the logging data.
Layers indicated by S wave velocity (red curve) inversed from surface wave of ambient noise data (SPAC method) can be verified by the logging data. (Tian You, 2018)
Natural earthquake observation
In XinJiang, China, researchers from Institute of geology and geophysics of CAS deployed 50 pieces of IGU 3C 5-Hz along a 25 km long survey line to study the crustal thickness with receiver functions through earthquakes of large epicentral distance. The station interval was 500-m, which is denser than arrays using for this kind of study.
A number of earthquakes with magnitude above Mw 6.0 from Japan and Indonesia have been recorded. The signal has high SNR with the main frequency around 2 Hz.
Station survey Map
The vertical component data applied with low pass filter with corner frequency 10 Hz. The magnitude 6.5 earthquake occurred in Indonesian at 15:35:01, Aug 17th, 2018.The epicentral distance is about 6500 km.
Shear wave velocity inversion from ambient noise
In October, 2018, a field deployment of SmartSolo nodal system was successfully conducted to record ambient noise data in Henan, China. The purpose of the project is to monitor levee safety of hydraulic systems. The SmartSolo system is very convenient for this purpose.
|Receiver point||10 set|
|Target||natural source surface wave survey|
|Channel count||IGU-16 1C 10 Hz，100 channels|
|Receive interval||2 m|
SmartSolo receivers were deployed in a triangular array.
The geometry of the triangular geometric receiver array
(Note: rotated -90 degrees, this is more conventional –Lanbo Liu)
S wave phase velocity dispersion curve extraction
SmartSolo receivers were deployed in a triangular array on the levees.