Seismometers

SE3W Wireless Remote Seismic Acquisition Unit

( Overview

Photo Icon 01 Photos
 
Modern Portfolio Image

Uses high-level integration technology, the SE3W unit is designed to fit in your palm. Its primary usages include natural seismic monitoring, natural surface wave monitoring, and wide-angle seismic monitoring. Its wireless design greatly improves ease-of-use.

 
 

( Main Function

Photo Icon 02 Photos
 
Refraction and Wide-Angle Reflection Methodology:

usually uses explosive sources. To get a signal from the earth's crust and upper mantle requires placing tens to over a hundred mobile seismic telemetry units in a line hundreds of kilometers to over a thousand kilometers long (each telemetry unit separated by 1 - 10 km). The data acquisition system collects all the seismic data. This methodology gives a relatively precise cross-sectional contour plot of the refracted wave speeds which can be used to compare with known properties of rock as an indicator of the subterranean composition.



Near-source Vertical Reflection Methodology:

is divided into two types: explosive sources and non-explosive sources. Non-explosive sources are hammer, continuous vibration, gas explosion (air gun) and electroseismic source. Due to the low power of vibration sources, only near-source reflected waves can be detected, so the surveying range is relatively short (<10 km) and telemetry units are relatively close together (50 - 100m). Field procedure uses synchronized excitation, synchronized sensing, and multiple pattern sweeps by the numerous channels. Using statistical methods to suppress irregular and regular interference waves, a high signal to noise ratio and high resolution signal can be achieved. Some data processing then yields speed interface data, fault occurrences, plate contact data, and the presence of oil or gas strata.

Microseismic monitoring:

microseismic monitoring is a recently developed technology. It can be divided into two types: natural and artificial sources. Natural sources include wind, ocean waves, volcanic activity, plate tectonics, surface rock motions and other natural phenomenon. Its earlier uses included the assessment of foundations in construction. After the 60's, it was applied in landslide monitoring, geothermals, and other fields. Artificial sources of microseisms primarily arise from traffic, machinery, and artificial fracturing, explosive mining, and other such sources. Recently, illegal mining, mining zone regulations, hydrofracturing, geothermal surveying, CO2 storage monitoring, etc. It is widely applied in the areas of environmental monitoring and microseismic monitoring.

Natural-source Surface Wave Surveying:

microtremors can be viewed as a random yet stable process - it is a natural phenomenon that changes to a degree with position and time. The microtremor history of a particular time interval can be used to determine its stochastic properties. This is then used to find the dispersion curves, which are in turn used to calculate the earth's wave speed composition.

 
 

( Main Features

Photo Icon 03 Photos
 
This handheld, waterproof:

dirt-proof device is the size of a walkie-talkie, features a built-in field-swappable lithium battery, and has a gross weight of 250 grams.

High-precision ultra wideband

3 built-in 24bit high-precision channels, can connect 3-axis velocity and acceleration sensors. Channels have ultra wide bandwidth (0-500Hz), has 126dB dynamic range at 10-1000Hz sampling rate

High sampling rate, versatile design:

highest sampling rate 1kHz, up to 4GB/ch

high precision synchronization

built-in high sensitivity, high precision synchronized GPS (synchronization error less than 30ns, position error 3m), wireless communication, high capacity microSD card (4-16 GB) data storage. Each unit has a unique 64bit identifier. Timing can be controlled by scheduling, wirelessly, event-based, etc.

built-in wireless communication network:

the SE3W can, as needed, be expanded into a 3 part system composed of wireless acquisition units (RSU), on-site central station (CSU), and remote control unit (KCU). the built-in wireless network module uses Digi's wireless network module. Each CSU supports up to 256 RSU's. In addition to monitoring RSU work, the CSU monitors environment parameters such as temperature, humidity, rainfall, wind speed, wind direction, etc for evaluation of the reliability of the data. The KCU, via GPRS, controls the CSU (and through it, the RSU), receiving data in real-time. If required, the RSU can also install the GPRS module for direct communication with the KCU.

 
 

( Pictures

Photo Icon 04 Photos
 
 
 

( Technical Specifications

Photo Icon 05 Photos
 
Number of channels: 3
Bandwidth: 0~6kHz
Dynamic Range: 126db
A/D converter: △Σ24bit
Sampling rate: 2.5 Hz - 30 kHz (15 selectable settings)
Sampling data length: 4 GB/ch at 2.5 - 1 kHz, 8 KB/ch at 2kHz - 20 kHz (expandable)
Largest input voltage: 10v
Equivalent input noise: 0.6 uV (at 1 kHz sampling rate)
Input resistance: 30kohm
Core processor: ARM9
Built-in GPS: timing error 30 ns, positional error 3 m, sensitivity 146 dBm
Built in wireless communication: 2.4 GHz, line of sight range 3.2 km, actual range in mountainous terrain 300 m, communication speed 250 kbps, maximum number of nodes 65535
Memory: 4 - 16 GB micro SD
Monitor: 128 x 32 pixel reflective screen with backlight
Average power consumption: operating 140 mA, standby 30 mA
Battery: 7.2V / 1.6 Ah, 10 hours operating time or 50 hours standby. Compatible with external battery or solar cell.
Size: 100mmX60mmX40mm
Weight: 250克
Operating Environment: -20 to 65 degrees Celsius, rainproof
 
 

The SE3W has rich software support, which fall under two categories: data acquisition and data processing.

Data acquisition software:

It is primarily for the acquisition, storage, replay, and real-time monitoring capabilities. can display acquisition parameters and control through the KCU. integrated control of all on-site acquisition stations

Processing software:

It supports both universal and specialized data processing software. can include general and specialized modules as needed; can include data management module. works with many commercial processing software and is highly expandable. The software includes (but is not limited to) data preprocessing, time-domain analysis, frequency domain analysis, amplitude domain analysis, modal analysis, microtremor analysis, hydrofracturing 4D scan, natural-source surface wave processing.

Data preprocessing:

It supports data editing and interval selection, smoothing, bias removal, derivatives and integration, digital filtering.

 
 

( Expandable Peripherals

Photo Icon 07 Photos
 
 
 
 
 

( Suggested Components

Photo Icon 09 Photos