Introduction

The 3ESPDC is a 60-second triaxial weak motion seismometer with an integrated CMG-CD24 digitizer. The compact size and moderate weight (8.3kg) makes it more portable than the the 3T or 3TD. The 3ESPDC has mass locking, unlocking and centering. Data can be directly downloaded from the instrument to an external hard drive via a firewire cable with a waterproof milspec connector. This can be performed whilst the instrument is buried.

The ESPDC has a new type of transfer function which creates high clip levels at high frequencies and a low noise floor at long periods, allowing one to use the dynamic range of the instrument more effectively. This type of instrument is most suitable for the study of body waves and shorter period surface waves.

Much of the information presented in this page is from Guralp.

 

Specification

Total number 40
Digitizer
Integrated CD24 digitizer
Masses
Three Orthogonal masses (XYZ). Automatic mass locking, unlocking and centering (within 2 degrees from the horizontal) by remote terminal command or via Scream!
Data output
GCF format to internal flash
Memory
8Gb or 16Gb of internal flash memory allowing approximately 120/240 days of recording three channels at 100 sps
Data download
Data can be moved from the internal flash memory to an external hard-drive via an IEEE1394 (firewire) port and cable.
System control
Instrument control is via Guralp software available on Windows and Linux platforms, as well as on waterproof Palm computers.
Power consumption
1.6W
Power supply
10-36V DC range.
Dimensions
Height: 258mm; Diameter: 168mm
Weight
8.3 kg for sensor alone
Frequency response
60sec to 50Hz
Sampling rate
1-200sps
Operating temperature
-40°C to 65°C
GPS
External GPS antenna

 

Shipping information

ESPDs ship in boxes containing 1 instrument, 1 GPS external antenna and all associated cables

Most projects use one or two 20W solar panels per instrument, details of which can be found here. 12v batteries (usually car batteries) should be provided by the user.

SEIS-UK is able to offer advice on the appropriate number of solar panels and batteries necessary for your period and latitude of deployment.

Instrument box dimensions 530mm x 400mm x 570mm
Instrument box volume 0.121m3
Instrument box weight 20kg
Solar box dimensions 720mm x 520mm x 390mm
Solar box volume 0.148
Solar box weight (5 panels) 32kg

Links and downloads

link: gurlap's operations manual for the ESPCD
Guralp's operations manual for the CMG-3ESPCD
link: PDF file of guralps' ESPCD data sheet
Guralp's CMG-3ESPCD data sheet