## 1 Introduction
Then, the data would be transmitted to application layers for data analysis and handle applications through various communication technologies and protocols, facilitated by gateways in the network layer [17]. The utilization of sensor-generated data inside IoT systems can facilitate data analysis and decision-making processes in the field of disaster management, provided that the data is successfully uploaded to the application layers [19]. Hence, the primary objective of this study is to address the research inquiries pertaining to both the pre-disaster and post-disaster stages. 1. What kinds of sensors are used to collect data? And what kinds of data are focused on the pre-disaster stage and post-disaster stages, respectively? We aim to present a comprehensive analysis of the sensors employed in many catastrophe scenarios, with a particular focus on investigating the feasibility of developing universal sensors capable of addressing multiple types of disasters during the pre-disaster phase. During the stage following a disaster, it is imperative to deliberate on the appropriate data to be gathered for the purpose of post-disaster management. 2. What kinds of communication technologies and protocols are used to transmit the data from sensors? We aim to examine the communication technologies and protocols employed during the pre-disaster stage, with the objective of identifying the prevailing and effective communication technologies and protocols. Additionally, we will examine the emergency communication technologies and protocols implemented during the post-disaster phase. The communication technologies and protocols utilized during the post-disaster phase differ from those employed in the pre-disaster phase due to the potential destruction of the communication infrastructure established prior to the occurrence of the disaster. 3. What methods were used to analyze sensor data? The enhancement of machine learning algorithms has the potential to reduce expenses associated with sensors and facilitate expedited disaster alert systems. Furthermore, the utilization of visual algorithms facilitates the detection of various types of disasters, such as floods and earthquakes, via cameras. Therefore, it is imperative to conduct an investigation into the processes of data analysis. 4. What are the differences between the IoT technologies used in the pre-disaster and post-disaster stages? Prior research has shown a greater emphasis on the utilization of sensors in the IoT for disaster management in the pre-disaster phase as opposed to the post-disaster phase. [PERSON] et al. [14] conducted a comprehensive review of early warning systems for natural catastrophes in the pre-disaster stage, specifically focusing on IoT. [PERSON] et al. [20]critically examine the utilization of affordable sensors in the monitoring of climate-related disasters in coastal regions. Nonetheless, it is imperative for disaster management to encompass many activities during both the pre-disaster stage, such as disaster identification and prevention, as well as the post-disaster stage, including evacuation, search and rescue operations, and rehabilitation efforts [21; 22]. Disasters can manifest abruptly or unexpectedly [6]. The likelihood of locating individuals who have survived a catastrophic event significantly decreases subsequent to the first 72 h period [15]. Efficient disaster response systems are crucial in order to mitigate human suffering and mortality rates [6]. Hence, we not only address the sensors employed in IoT systems during the pre-disaster stage but also emphasize the sensors utilized in IoT systems during the post-disaster stage. Additionally, we conduct a comparative analysis of IoT systems throughout the pre-disaster and post-disaster stages. In this study, our objective is to identify the prevailing technologies, such as sensors, communication technologies and protocols, and data analysis methodologies, that are utilized in IoT-based disaster management throughout both the pre-disaster and post-disaster stages.