Chapter 2. Introduction

The Flute-H/OBS instrument is a triaxial, very broadband, force-feedback seismometer in a 63.5 mm diameter (excluding protrusion) by 614 mm long (excluding connectors) titanium ocean-bottom package. The instrument can be field-configured to one of four pre-set frequency responses. It provides a differential velocity output as well as a mass position output for each of its three components.

The instrument is capable of self centring when installed at up to 30° from the horizontal (60° for the vertical component) and includes a hardware-activated auto-centre function for true autonomy.

The instrument contains a low-power processor which can be used to control the frequency response and to initiate centring (offset-nulling) but it can also be operated in fully autonomous mode: Once power is applied to the system, the sensors will centre themselves with no further input from the user. The processor can be controlled using logic lines or via a serial communication channel. This allows computer-control of additional functions, if required.