Expanding Concentric Search Grid
Definition
The systematic spatial framework for post-blast scene searches, consisting of concentric rings at measured radii from the seat of blast, divided into clock-face sectors, each assigned a unique cell reference for exhibit documentation.
- Reference point
- Seat of blast (crater or point of maximum damage)
- Structure
- Concentric rings at measured radii, divided into clock-face sectors
- Purpose
- Systematic recovery and unique cell referencing of exhibits
- Application
- Post-blast scene searches, e.g. IED or bombing investigations
Common questions
Why use clock-face sectors within each ring instead of a plain grid of squares?+
A post-blast scene radiates outward from a single point, so a polar layout of rings and sectors matches the actual damage pattern, letting searchers correlate fragment distance and bearing from the seat of blast, which supports reconstruction and yield estimation.
How far out does the search grid typically extend?+
The outer radius is set case by case from the observed blast damage pattern, such as window breakage and fragment throw, not a fixed distance, and is often extended in stages as the search team confirms the debris field boundary.
What does the unique cell reference on each ring-sector record?+
It ties every recovered fragment to its exact radial distance and angular position from the seat of blast, letting investigators later reconstruct the fragmentation pattern and estimate charge weight and device type.
Related terms
- Crater Glass
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- Ion Mobility Spectrometry (IMS)
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- JESIP
- Joint Emergency Services Interoperability Programme (UK); the framework mandating co-located multi-agency command with a shared decision log from initial response, applied to...
- Paint Transfer Analysis
- Forensic comparison of paint layer sequences (primer, base coat, lacquer) on near-field surfaces against reference samples to identify the vehicle or container...
- Render-Safe Procedure
- The action taken by a qualified EOD or bomb disposal team to make a blast scene or live device safe from secondary...
- Scene Log
- The contemporaneous record of every person entering and exiting the inner cordon, with time stamps and roles; the foundational chain-of-custody document for...
- Seat of Blast
- The precise point of initiation of the detonation, identified from the convergence of crater geometry, witness-mark vectors, damage gradient, and residue concentration.
- Sieve Recovery
- The process of collecting and dry- or wet-sieving soil and debris from the crater and innermost grid zone through 2 mm and...
- Witness Mark
- A fragment embedded in a structural surface (wall, column, vehicle panel) at a known position and angle, providing a directional vector back...