Chapter 2. Introduction

The Güralp Fortis is a three-axis, strong-motion, force-feedback accelerometer with an innovative, slim-line design for fast installation in any environment. The system has a flat response to ground acceleration from DC to 100 Hertz and a stable phase response within this passband.

Extremely low noise, a high dynamic range and switchable gain allow the instrument to perform optimally in a wide range of scenarios, providing versatility for all EEW (earthquake early warning) and structural health monitoring applications.

The hard-anodised aluminium casing protects the instrument from water, allowing it to be deployed in a range of environments. Installation is simple, using a single fixing bolt to attach the sensor to a hard surface. If required, you can also level the sensor using its adjustable levelling feet. An integrated bubble-level provides quick visual feedback.

Each accelerometer is delivered with a detailed calibration sheet showing its serial number, measured frequency response, sensor DC calibration levels and the transfer function in poles/zeroes notation.

Optionally, you can use a Güralp Hand‑held Control Unit (HCU) and/or breakout box to distribute power and calibration signals to the sensor and to receive the signals it produces. The HCU is available in standard, rack-mounted and water-resistant portable formats.

A version designed for post-hole deployments, the FortisPH, is also available. See chapter 3 for details.