Life detectors with seismic sensors - SEARCH

SEARCH seismic sensors are used during Urban Search And Rescue operations to detect and then locate the exact position of conscious buried victims following major incidents like an urban explosion (gas, attack, etc.) or natural disasters (such as earthquakes, structural collapses, avalanches, landslides, etc.).

Seismic sensors are also called “USAR listening devices/systems/equipment”, “seismic detectors”, “electronic search device”, “geophones”, “geostereophones”, “sound sensors” or “life detectors”.

SEARCH seismic sensors are one of the 5 peripherals used for Urban Search And Rescue operations. They are part of a rescue team’s toolkit, just like UWB radars and victim location cameras.

Ultra-sensitive for optimal sound quality in the search area, SEARCH sensors use seismic technology to detect the most subtle sounds/vibrations caused by a victim (scratching, hitting, shouting, etc.) under rubble and help triangulate their position.

WHAT IS SEISMIC/ACOUSTIC LISTENING TECHNOLOGY? AND HOW DOES IT WORK?

Thanks to seismic technology, SEARCH seismic sensors detect the smallest vibration caused by a victim buried under rubble (scratching, hitting, shouting, etc.) by using the collapsed structure like a giant microphone.

Seismic sensors are geostereophones (wave receivers). They sense vibrations which resonate and circulate in the different materials of the collapsed building and amplify them via a control box. The rescuer can “listen” via audio headsets and “view” the audio signal via a bar chart on the control box for vibrations made by victims buried under the rubble.

HOW ARE SEISMIC SENSORS USED? OR HOW DO SEISMIC SENSORS WORK?

Firstly, the rescuer places the seismic detectors (generally positioned in a line) on the floor, in contact with the rubble.

Next, the rescuer bangs on the concrete slabs and shouts to ask victims to reply.

They then listen in total silence and wait for the victim’s “response” (scratching, hitting, shouting, etc.) to help locate them.

If no vibration is observed, the rescuer continues through the zone to be covered, repeating the same method. The objective is to map the zone by identifying the location of buried victims.

If the sensor receives a signal (represented by sounds in the audio headset and via an active bar chart on the control box), the rescuer will leave the sensor in the same place with the strongest signal, and will then move the other sensors to triangulate the zone and refine the position.

The position of the victim is identified when all sensors have a signal at the same intensity.

FEATURES OF SEISMIC SENSORS

SEARCH seismic sensors offer exceptional sound quality and efficient sound transmission allowing effective life detection. Designed to be rapidly deployed and easy to use, it quickly determine the sources of sound and thus the precise positions of potential victims. The seismic detectors are able to detect vibrations from 20 to 3000 Hz.

SEISMIC SENSORS SPECIALLY DESIGNED FOR SEARCH AND RESCUE OPERATIONS

SEARCH seismic sensors were specifically developed for search and rescue operations. Compact and lightweight, SEARCH seismic detectors only weigh 690 g and can be easily placed in a pocket. IP67-rated, they are totally protected against dust, and are not affected by water splashes. Fitted with a carry handle, they are easy to transport. Finally, they are equipped with a flexible antenna allowing optimal connectivity between the sensors and control box. Wireless sensors are powered with three AAA batteries for 8 hours running time. They are easy to replace and avoid the use of special batteries and the associated charge. Wired sensors are powered by the control box via their cable.

TWO TYPES OF SEISMIC SENSORS: WIRELESS OR WIRED

INTERFACE AND MAIN FUNCTIONS

Intuitive and ergonomic, the navigation interface is very easy to use. It only requires minimal training to be used by rescuers.

Each seismic sensor connected to the control box is represented on the screen with a bar chart. The levels of signals detected by the sensors are shown on the screen through:

• Yellow bar charts indicating the intensity/strength of the signal,
• A yellow marker indicates the maximum level of signal detected by a sensor.
• A red marker represents the highest seismic peak detected amongst all sensors.

When a vibration is caused by a victim, the bar chart corresponding to the sensor closest to the victim will show a higher bar on the screen than the other bar charts.

ADJUSTABLE NOISE FILTERS

The control box, which acts as the “brain”, has two adjustable noise filters to eliminate noise interference (low/high-pitch) from nearby rescue teams (pneumatic drills, site machinery, wind, power cables, etc.).

• The “filter high” function accesses a low-pass filter setting which removes high-pitched noise. The function removes frequencies above the setting threshold (setting threshold: 600 Hz to 3000 Hz).
• The “filter low” function accesses to a high-pass filter setting which removes low-pitched noise. The function removes frequencies below the setting threshold (setting threshold: 20 Hz to 300Hz).

TWO LISTENING MODES

Vibrations/sounds detected by seismic detectors can be “listened to” in “Mono” mode or “Stereo” mode to listen to noises with one or two ears, allowing a large variety of listening combinations.

• “MONO” mode: listening to the sensor(s) in both ears.
• “STEREO” mode: listening to the sensors in the right or left ear.

SEARCH seismic sensors offer exceptional sound quality and sound transmission allowing effective life detection.

Designed to be easily and rapidly deployed, seismic detectors help quickly determine the sources of sound and so the precise positions of potential victims.

EXISTING PREDEFINED KITS

Below are all the predefined kits using the “SEARCH - seismic sensors” peripherals as standard and as an option.

=> Discover the MULTISEARCH concept and all peripherals, existing kits and accessories in our catalogue at the following link: USAR catalogue

=> Need more information?
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