We present a Risk Atlas of Mexico City based on a Geographical Information System (RA-GIS). We identified the prevalent social risk to the more relevant hazards in Mexico City (CDMX): earthquakes, volcanic eruptions, floods, landslides, forest fires, and land subsidence. A total of 274 shape-file maps were generated in this project. Seismic hazard was estimated for return periods (RP) of 20, 125, 250, and 475 years. Three areas in central and northwestern CDMX were identified along the Younger Chichinautzin Monogenetic Volcanic Field with a high probability of forming a new volcano. Subsidence is concentrated to the east and southeast of CDMX, where subsidence rates are among the highest worldwide. Flooding events were estimated for RP of 2, 5, 10, 50, and 100 years, and most of them are concentrated in the central and northern sectors of the city. During the dry season (December–April), southern CDMX has very high probability of forest fire occurrence. There is high susceptibility of landslides on the west and southwest of the city. The goals of this RA-GIS are to provide a tool to the local and federal authorities and all organizations responsible for disaster prevention and mitigation to: (1) improve the knowledge of the potential physical and social impact of local hazards; (2) provide elements for disaster prevention, mitigation, preparedness, and response; (3) benefit decision-makers with robust risk data; (4) provide information for land-use planning; and (5) support further research to reduce the impact of disasters caused by natural phenomena.

On 4 January 1920, a magnitude $Mw$ 6.4 earthquake occurred in the eastern Trans‐Mexican volcanic belt (TMVB) to the southwest of the city of Jalapa, Mexico. Structural damage was extensive in towns near the epicentral area. The more damaging phenomena, however, were mudflows in the high valleys that covered several villages. It was estimated that approximately 700 people died under the mud avalanches triggered by the earthquake on the steep slopes of the river valleys. The moderate‐sized 1920 Jalapa earthquake is the second deadliest earthquake in the history of Mexico and the only one in which extensive mudflows triggered by the earthquake were reported. Several active faults mapped in the central part of the Mexican volcanic belt have produced earthquakes as large as $Mw$ 7.2. In the eastern portion of the belt, where the Jalapa earthquake took place, few faults have been mapped. Therefore, there is doubt about whether the 1920 earthquake was a shallow, crustal earthquake or whether it occurred within the subducted Cocos plate, as with other earthquakes located to the south of the TMVB. In what constitutes probably the first aftershock study after a destructive earthquake, the Mexican Seismological Service installed an 80‐kg, Wiechert vertical seismograph in the city of Jalapa after the earthquake. The S–P times of three aftershocks indicate that they occurred in the epicentral area, confirming it as a shallow crustal earthquake. This pioneering aftershock study helps confirm that crustal seismicity extends throughout the TMVB, where 40% of the population of Mexico lives.

Due to its geographical location, the community of Motozintla de Mendoza (Motozintla) in the State of Chiapas, Mexico, is continuously exposed to the impact of natural hazards. In this work, we assessed the flood risk of Motozintla considering the structural, socioeconomic, organizational, and global (structural, socioeconomic, and organizational) vulnerabilities. In addition, we also measured the local risk perception. Spatial maps were generated to determine the most vulnerable and risk areas of this community. Our results indicate that the population has a high level of risk to flooding mainly because (1) the majority of the local houses has high structural vulnerability; (2) a high percentage of the families has a daily income less than the official Mexican minimum wage and lacks of basic public services as well as of proper social security services; (3) most of the community does not know any existing Civil Protection Plan; and (4) the community organization for disaster mitigation and response is practically non-existent. For these reasons, we believe that it is necessary for local authorities to establish in the short-term, preparedness, mitigation and response plans as well as land-use measures to reduce the risk to floods in Motozintla.