Introduction
Every urban space, including historical fabrics, due to their potential and identity value, must be resilient, and the vulnerability of such spaces should be minimized. To achieve the objectives of passive defense in cities and their valuable textures, such as historical fabrics considered as city assets, reducing vulnerability and risk should be addressed through urban planning and design strategies. These include respecting adjacency principles, enabling emergency evacuation, establishing temporary shelter centers, storage centers for essential supplies, fostering a sense of belonging among residents, appropriate dispersal and distribution of key land uses, as well as access and buffer zones.
The historical fabric of Khoy city includes the traditional market, Matlabkhan Mosque, Seyyed al-Shohada Mosque, Sangy Gate, and others, located in the central core of the city, which also lies within the worn-out urban fabric. Due to its historical values and tourist attraction, Khoy city holds significant importance from the perspective of passive defense and resilience. Therefore, safety and security studies of Khoy’s historical texture must be conducted to identify areas with high vulnerability and risk, and ultimately to derive urban planning and design solutions to enhance the resilience of its historical fabric.

Methodology
The present study is applied in terms of its objective and employs a descriptive-analytical approach in terms of method. Initially, through library and documentary studies—such as reviewing relevant literature, previous research, and expert theories in the field—the key assets and their probable threats in the study sample were identified. For data analysis, the Analytic Hierarchy Process (AHP) model (used for weighting evaluation criteria of assets, threats, and vulnerabilities) and the FEMA (Federal Emergency Management Agency) model (used for risk assessment) were employed.
Experts in the field of architecture and urban planning and passive defense were identified in consultation with academic supervisors. A total of 30 experts were selected as the statistical population for completing the questionnaire using a census method. From these, 28 individuals responded and were considered as the sample size based on Cochran’s formula.
The risk formula used in this study is as follows:
Risk = Asset Value × Threat Level × Vulnerability Level

Results and discussion

Identification and Evaluation of Key Assets
In the first stage, key assets of the fabric were identified through the expert community and field visits, followed by valuation. The results indicate that among the historical assets of Khoy, the Traditional Market scored 7.7, Qamar Bani Hashim Hospital 7.62, Tax Administration Building 6.2, Registry Office Building 16.6, and the Central Square (Imam Square, Central Crossroad) 5.88, having the highest values.

Identification and Evaluation of Threats to Key Assets
In the second stage, threats to key assets were evaluated via expert community assessments and questionnaires. The results show that the most probable threats to Khoy’s historical fabric assets include sabotage and intentional destruction, arson, aerial attacks, riots, and psychological operations.

Assessment of Vulnerability of Key Assets to Threat Occurrence
In the third stage, vulnerability resulting from threats to key assets was assessed through expert surveys and questionnaires. Findings reveal that the highest vulnerability of Khoy’s historical assets is against aerial (missile) attacks, ground assaults (artillery, mortars, etc.), terrorist attacks (car bombings), espionage and human infiltration, as well as riots and psychological operations.

Risk Assessment of Key Assets Against Threats
In the fourth stage, the risk resulting from threats to key assets was evaluated through expert community assessments and questionnaires. The cumulative highest risks were assigned to the Post Office, Khoy Traditional Market, National Bank Central Branch of Khoy, Registry Office Building, former Telecommunications Building, Central Square (Imam Square), Tax Administration Building, Police Station No. 1 (former Shahrebani), Amir Kabir Passage, Khan Caravanserai, Old Municipality Building, Mostazafan Passage, Eghtesab Passage, Khosravi School, Khoy Museum and Old Library Building, and Ettehad Passage, respectively.

Conclusion
In the present study, the risk of key assets in the historical fabric of Khoy city was evaluated using the FEMA (Federal Emergency Management Agency) method. The risk assessment was conducted in three stages: asset identification, threat analysis, and vulnerability evaluation. In each of these stages, asset, threat, and vulnerability maps were produced within a GIS software environment.
In the asset identification phase, 16 key assets were identified based on expert opinions and subsequently evaluated using criteria approved by the Passive Defense Organization. Following this, the threats, vulnerabilities, and risk levels of each key asset in the fabric were calculated.
Finally, the following recommendations are proposed to reduce the risk in the historical fabric:

• Locating and designing multi-purpose safe spaces (multi-purpose emergency shelters) within the fabric, preferably adjacent to main roads.
• Avoiding the introduction of new land uses with vital importance inside the fabric.
• Locating temporary shelter centers within the fabric, such as green spaces, sports complexes, religious, and educational facilities.
• Considering small emergency units, such as fire stations, in the central part of the fabric.
• Creating and organizing a street network that facilitates rapid evacuation and emergency response inside the fabric.
• Increasing permeability in high-traffic areas of the fabric’s key centers.
• Designating special routes for emergency vehicles at the main square of the fabric.
• Planning alternative routes for paths prone to blockage.
• Widening narrow main streets inside the fabric to allow the passage of emergency vehicles.
• Maintaining a 300-meter buffer zone around hazardous land uses (those with potential for explosion, fire, or toxic emissions) relative to key assets inside the fabric (corresponding to the blast radius of a 2000-pound TNT bomb).
• Relocating military land uses (excluding law enforcement such as police stations) outside the fabric. Vacated military sites should be repurposed as brownfields to address crisis management service shortages in the fabric.
• Reducing obstruction, especially in the traditional market.
• Educating residents of the fabric on necessary actions during crises, including engaging market merchants through building trust with the Cultural Heritage Organization of the city.
• Reducing activity density in highly congested centers, with emphasis on the core of the fabric.