Seat of Explosion
Definition
The physical location at the centre of an explosion, identified by maximum crater depth, convergence of fragment-throw vectors, and highest damage density. The primary sampling location for explosive residue, as it contains the highest concentration of main charge residue.
- Primary identifier
- Deepest crater and maximum localized damage zone
- Key evidence type
- Highest concentration of main charge explosive residue
- Sampling role
- Central location for post-blast residue collection (IMS, GC-ECD, LC-MS/MS analysis)
Common questions
How do investigators locate the seat of an explosion at a scene?+
Investigators identify the seat of explosion by looking for the deepest crater at ground level, the area with maximum localized damage, and where fragment scatter vectors converge. These markers pinpoint the physical location where detonation actually occurred.
Why is the seat of explosion important for forensic sampling?+
The seat of explosion contains the highest concentration of explosive residue from the main charge, making it the primary location for sampling post-blast material. Testing residue from this location yields the most meaningful chemical evidence.
What physical evidence does the seat of explosion show?+
The seat shows the greatest damage density in its immediate surroundings, and fragments thrown outward follow patterns that radiate from this central point. These patterns help reconstructionists understand both the explosion's force and direction.
Related terms
- Blast Over-Pressure
- The shock-wave pressure above ambient atmospheric pressure. Mapped in concentric zones around the seat: Zone I (over 70 kPa, total destruction), Zone...
- BNSS Section 176(3)
- Bharatiya Nagarik Suraksha Sanhita 2023 provision requiring a forensic-team visit to the scene of any offence punishable with seven years or more...
- CFSL Hyderabad Explosives Wing
- The explosives examination section of India's Central Forensic Science Laboratory in Hyderabad, the designated court-certifying facility for explosives analysis in major Indian...
- Control Swab (Background)
- A swab collected from an uncontaminated surface outside the outer cordon of a blast scene, processed identically to scene swabs, to establish...
- Crater Analysis
- Measurement of crater diameter, depth and ejecta direction at the seat of explosion. Feeds Hopkinson-Cranz scaling to estimate explosive type and charge...
- GC-ECD
- Gas chromatography with electron capture detection. Achieves 1-10 picogram detection limits for nitroaromatic (TNT, DNT) and nitramine (RDX, HMX, PETN) explosives. Cannot...
- Ion Mobility Spectrometry (IMS)
- A field-deployable analytical technique that separates ions by their mobility in an electric field at atmospheric pressure. Used for trace explosive detection...
- Multiple Reaction Monitoring (MRM)
- An LC-MS/MS acquisition mode in which the first quadrupole (Q1) selects a precursor ion at a specific m/z, the second (Q2) fragments...
- NIST SRM 8806
- A National Institute of Standards and Technology Standard Reference Material for explosive residue analysis, providing certified reference solutions of TNT, RDX, PETN,...
- NSG SAG and Bomb Squad
- National Security Guard Special Action Group plus Bomb Disposal Unit. India's first call for major terrorist devices; renders safe and supplies post-blast...
- Nylon-11 Bag
- Specialised fire-debris bag (Tinius Olsen pouch) that does not leak light hydrocarbons. Polyethylene bags are forbidden because they let pentane, hexane and...
- Quart Metal Paint Can
- Standard ASTM E1413 container for fire-debris samples. Holds volatile residues for charcoal-strip extraction (ASTM E1412). Unlined cans preferred for hydrocarbon accelerants.
Explained in these topics
- Investigation of Explosion and Arson CasesThe point of detonation, identified at the scene by the deepest crater, maximum localised damage, and the geometric centre of fragment dispersal.
- Post-Blast Residue Sampling and the IMS, GC-ECD, LC-MS/MS WorkflowThe physical location at the centre of an explosion, identified by maximum crater depth, convergence of fragment-throw vectors, and highest damage density. The...