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A New Approach to Mass Space

The analysis tools used by security professionals to assess asymmetric threats (such as a terrorist vehicle bombing) in respect to mass events or gathering places in complex urban environments rate poorly. A rethink is needed.

What Is the Problem?

The 2007 Haymarket attack in London, while it was not ultimately successful, demonstrated a key problem in the way that we think about counterterrorism. Firstly, the perpetrators were able to exploit the complex urban environment in central London and deploy vehicle laden improvised explosive devices (IEDs). Secondly, these vehicles were found in unobtrusive locations, and were only identified through pure luck.

  • The first vehicle laden IED was reported to the police by an ambulance crew attending a minor incident at the Tiger Tiger nightclub when they noticed suspicious fumes.
  • About an hour later, the second vehicle with an IED was ticketed for illegal parking and an hour after that transported to a car pound where staff noticed a strong smell of petrol and reported this to police when they heard about the other incident.

Very little in the way of tool development has been initiated to tackle the problem of assessing potential attacks in complex surroundings, where a variety of attack vectors are available to potential perpetrators. This is often compounded by the lack of intelligence-based threat assessments.      As mentioned, urban environments are complex. Military, security, and police engagements in cities are extraordinarily difficult given topography, urban development, and the close way in which urban societies are mixed together. Three factors typify the counterterrorism problem in civil urban settings:

  1. This is a non-combat environment. Contrast this with a combat zone, where all persons/objects encountered can be treated unfriendly.
  2. Attacks are typically unpredictable, often involve deception, and are frequently staged so that multiple vectors converge simultaneously.
  3. Little in the way of tactical language exists to describe sufficiently multi-dimensional or simultaneous tactics beyond the traditional lexicon, of two-dimensional conventional tactics.

Given this, Jeremy Black’s observation is particularly worrisome: “Future theatres of conflict will undoubtedly be urban and involve the world’s great population centres.”1 So in a sense, we are always going to be dealing with the analysis of urban mass gatherings. Yet how are these places to be understood from a military, security, or policing perspective? As well, problematically, there are multiple definitions of mass gatherings.

What is a Mass Gathering Space?

Several definitions of urban mass gatherings are used internationally. As an example, we will look at three of the more commonly used definitions.

  1. The Australian Attorney-General’s Critical Infrastructure Protection Branch, for example, describes places of mass gathering in terms of categories “including sporting venues, shopping centres, business precincts, cultural facilities, hotels, public transport hubs and major planned events.”2
  2. The U.S. Department of Homeland Security alternatively tends to use a proximity definition describing urban mass gatherings as “attendees, participants, and support personnel who physically remain in the same constrained location.”3
  3. The World Health Organisation (WHO) defines mass gathering events as “A gathering of persons usually defined as more than a specified number of persons (which may be as few as 1,000 persons although much of the available literature describes gatherings exceeding 25,000 persons) at a specific location for a specific purpose (a social function, large public event or sports competition) for a defined period of time.”4

The WHO definition includes the notion that a mass gathering is an event where the number of people attending is sufficient to strain or overwhelm the planning and response resources of the community, state, or nation hosting the event. This proviso is also included in the Australian government’s extended definition. As we can see, three essential themes emerge. A mass gathering can be defined as

  • category or class,
  • proximity, or
  • overwhelming event.

Of these definitions, the U.S. Homeland Security approach–a proximity test–fits closest to the issues that are important. In particular, it deals with the analysis of a mass gathering in terms of its internal dynamics:

  • proximity,
  • effects of blast, and
  • large volume movement.

      We also need to consider the information issues that arise when many people are in close proximity and confined in localized spaces. These add to the overall confusion and complexity from a human perception and informational view.

The 3D City Space

Mass gathering spaces are highly complex, incorporating features such as urban multi-level buildings, open spaces between buildings, crowd congregation points, and transport hubs within city central business districts (CBD). Conventionally, when we talk about the third dimension we are commonly referring to the airspace above the terrain. In the urban environment of today’s CBD, building heights typically range between 35 m and 55 m, although the tallest buildings top out at hundreds of meters. By way of comparison, the Sydney Tower observation deck sits at 250 m and the maximum height limit for Sydney buildings is currently 279 m.      From a definitional view, the third dimension in urban environments can be described as the full three-dimensional solid forms of buildings and spaces formed between buildings. These forms correspond closely to the typical 300 m2 weapons effective range for rocket-propelled grenades, small arms, and the kill zone in most bomb-blast radii. Operating in this environment, the current understanding is that to “maintain security requires the practice of spherical security.”5 In other words security, policing, and military operations must maintain a tactical security bubble devoid of back doors and rear areas.      In the chaos of the CBD is there any discernible pattern that would allow a security analyst to assess a Haymarket-styled attack in a mass gathered location? The answer to this question is found in examining vulnerability clusters.

Vulnerability clusters

A phenomenon increasingly noted in counterterrorist analysis of complex spaces is clear linear runs, where the terrorist can opportunistically seek out links between attack opportunities and vulnerabilities such as those found in multi-level buildings, large transit spaces, covered rail stations, plazas, commercial precincts, and malls. An example of this would be the 2007 Haymarket attack, where vehicle laden IEDs were discovered parked near the Tiger Tiger nightclub in Haymarket and Cockspur Street.      The vehicles were Mercedes, and given the high-status area represented by Haymarket, could be considered typical and unobtrusive for this time of day and location. Figure 1 represents a simplified model of the 2007 Haymarket attack as a 3D tactical model.6

Figure 1: The 3D tactical environment–identifying where opportunities (O) and vulnerabilities (V) link to become targets (T).

Figure-1      The figure illustrates the link between two vulnerabilities (V3 and V4). Because these are located on a transport line (the “arrow” illustrated in figure 1), they become potential opportunities to target. This simple illustration can be used to develop a mass-space security analysis in a complex public area where many potential targets and opportunities exist. For instance, in the case of the deployment of a vehicle laden IED in Haymarket, the Tiger Tiger nightclub itself was potentially a target, as was the busy street traffic and the crowd of people attracted to the area. In particular, these IEDs were effectively located in central London and placed in one of the main nightlife districts, only a short distance from Piccadilly Circus in the very heart of London\’s tourist district. The point here is that these potential targets are all linked along the street transit. Figure 1 again demonstrates the basic concept. This can be summarized in the following way:

  • An open space between two built areas (identified as buildings “A” and “B”) is identified. Within this area there are many vulnerabilities and these are represented as V1 to V4.
  • Only certain vulnerabilities can, however, be paired with opportunities.
  • These paired “V+O” are linked linearly by some common line of transport (for example, a road), thus allowing these to be targeted.
  • The line of linked vulnerability targets (V3 and V4), however, presents an attacker with multiple opportunities; that is, the attacker could either concentrate on V3 or V4.
  • An attacker adopting a route into the site which threatens multiple targets (V3 or V4), potentially will throw military, security, or police off-balance strategically, unable to protect any one target, and spread too thinly to protect all effectively from attack.

      In the 2007 Haymarket attack, the vigilance of ambulance crews and parking staff were key to identifying the vehicles. However, given that it was purely happenstance that these weapons were identified at all, a basic tactical problem remains: How can we more effectively see what is tactically taking place in our environment? The approach advocated here is training in 3D tactics, and a key aspect of this is better linear modeling.

Linear Modeling

An examination of urban building groups or even single buildings typically reveals that all urban space is reducible to set street and facade geometries which conform to distinct linear patterns. Viewed two- or three-dimensionally, we see repeating patterns of clear linear connections between access and exit from various spatial locations. From a tactical viewpoint, city streets appear as lines of access connecting buildings and spaces that can be targeted. We can also see

  • various critical components of a building,
  • vertical linear integration between street access points into a building, and
  • critical points located within the structure of a building (such as the elevator core, fire stairwells, plant rooms, ventilation and services systems).

      For example, a typical high-rise building with a street or corner frontage will be accessible by street (in the case of the deployment of a vehicle laden IED). Depending on the direction of street traffic, a typical building will present a street-frontage of 40m to 100m and incorporate access to loading docks and car parking. The building foyer area will also be exposed. Thus, clear patterns and connections can be identified within complex spaces and among seemingly diffuse vulnerabilities, opportunities, and targets. Fundamentally, from a purely tactical view, the counterterrorism problem in a modern urban context is framed by two observations:

  • Modern urban layouts (streets and buildings alignment and facades, etc.) quite closely produce a linear tactical model.
  • This suggests a return to linear tactics (more typical of earlier warfighting periods).

      The “analysis problem” is compounded by the fact that in any major city we see complex spaces, and the diffusion of many vulnerabilities and potential targets spread three-dimensionally through urban settings. Thus, along urban linear routes (roads, transport, or building thoroughfare) an attacker moving along these can threaten multiple targets. Again, this raises the basic tactical problem of the 2007 Haymarket attack–namely, military, security, or police forces are kept strategically off-balance, unable to protect any one potential target, and spread too thinly to protect all assets effectively from attack.
      In light of this issue, where does this leave us, with the reliance on intelligence-based threat assessments? The critical sub-problem to this issue is the need for a framing methodology that explains how an attack plays out in spatial, temporal, and human terms from a consequence analysis viewpoint. However, this is not easy to achieve. What is needed is development of a methodical evidence-based approach to vulnerability analysis within a 3D matrix.

  1. Black, Jeremy. “War and the New 21st Century Disorder,” Australian Army Journal, Volume III, Number 2, Winter 2006, p. 54. []
  2. Australian Commonwealth Government: National Counter-Terrorism Committee (2006) National Approach for the Protection of Places of Mass Gathering from Terrorism. pp.1-3. []
  3. U.S. House of Representatives, Committee on Homeland Security, Public Health, Safety, and Security for Mass Gatherings, May 2008, p. 3. []
  4. World Health Organization, Communicable Disease Alert and Response for Mass Gatherings: Key Considerations, June 2008, p. 7. []
  5. Ackerman, R.K. “Training, Not Technology, Is Key to Urban Warfare,” SIGNAL. May 2001. http:// []
  6. This model was first presented in the following article: Flaherty, C. (16/17 July, 2007) “Mass Space Vulnerabilities Analysis in 3-D Tactics,” International Crime Science Conference. University College London, Centre for Security and Crime Science. Proceedings on CD-ROM format. []

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