Guralp Systems Limited
MAN-040-0001 Güralp 40T User's Guide

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1. Preliminary Notes 2. Introduction 3. First encounters 4. Installing the 40T 5. Calibrating the 40T 6. Connector pin-outs 7. Specifications 8. Revision history

Section Index: 2.1. Response options

Chapter 2. Introduction

The Güralp 40T is an ultra-lightweight seismometer consisting of three sensors in a sealed case, which can measure the north/south, east/west and vertical components of ground motion simultaneously.

The 40T has a rugged, waterproof stainless steel design for ease of installation. The lightweight sensor elements are designed so that no mechanical clamping is required. Because of this, the 40T is ready to record ground movements as soon as you provide it with power. In addition, the sensor does not have to be levelled or centred as long as the base is within 3° of horizontal. For the best results, however, you should install where possible on a hard, near-horizontal surface well coupled to the bedrock.

Each seismometer is delivered with a detailed calibration sheet showing its serial number, measured frequency response in both the long period and the short period sections of the seismic spectrum, sensor DC calibration levels, and the transfer function in poles/zeros notation.

2.1 Response options

The 40T can be supplied with a response which is flat to velocity from 50 Hz to any of 0.1 Hz (10 s), 0.050 Hz (20 s) or 0.033 Hz (30 s).

If you do not require high-frequency data, a low-pass filter may be installed at a frequency (below 50 Hz) that you specify.

Standard 40T instruments output signals representing ground velocity on three pairs of balanced differential lines. An option is available which provides a second, parallel set of outputs at higher gain. The high-gain outputs have a sensitivity nominally 10 times higher than the standard (low-gain) outputs.

PreviousNext

1. Preliminary Notes 2. Introduction 3. First encounters 4. Installing the 40T 5. Calibrating the 40T 6. Connector pin-outs 7. Specifications 8. Revision history