What Happens If Mount Fuji Erupts? How Well Is Your Company Prepared?

Introduction

suddenlyHowever,What would happen if Mount Fuji erupted?Can you answer the question, "..."?
It's natural for many people to imagine that volcanic ash might fall. However, the real problem is "what to do if there are warning signs" and "how to prepare for business operations if infrastructure is shut down."
Even after the Cabinet Office guidelines were issued in 2025, the reality is that "only a few companies have made concrete preparations." If this continues, they will suffer significant damage if a disaster strikes. Therefore, this time,Mount Fuji eruptionThis article will explain in detail how companies should prepare for such an unprecedented disaster.

1. The past and omens of Mount Fuji: Understand that there have been no major eruptions for over 300 years.
2. The reality of infrastructure damage caused by volcanic ashfallLearn about the specific impacts on transportation networks, power, communications, etc.
3. Current Status and Challenges of Corporate BCPs (Business Continuity Plans)
4. Practical preparations you should learn about, such as "evacuation" and "working from home."

This article will help you not only understand disaster risks but also how to apply them to your work and daily life.

A Mount Fuji eruption is an "unprecedented disaster," which is why preparation is crucial.

There have been no major eruptions of Mount Fuji since the Hoei eruption more than 300 years ago. However, it is dangerous to think that "there is no need to worry because it hasn't happened in a long period of time." Volcanic activity can have warning signs, and if these signs are missed and the response is delayed, the damage will spread.

The most important point I wanted to convey in this article is: **The fact that, unlike earthquakes and floods, many companies are not adequately prepared for a Mount Fuji eruption.** According to a Cabinet Office survey, only about 251 TP3T companies have a BCP (Business Continuity Plan) that anticipates a volcanic eruption and ashfall. This is lower than the percentage of companies prepared for the following disasters:

• Earthquakes and tsunamisOver 90% of companies have countermeasures in place.
• Flooding (such as water damage)Over 50% of companies have already taken measures.
• Preparation for infectious diseases: A higher percentage of cases have countermeasures in place.

Why are preparations for volcanic eruptions lagging behind? Many companies tend to fall into a state of "mental paralysis," thinking, "We don't know when it will happen," or "The damage will be too great to do anything." However, even a delayed response can mitigate damage if the initial response to a disaster is swift.

Key points:
Some companies (such as Canon MJ) have established initial response measures such as "If there are any warning signs, executives should leave Tokyo." It is necessary to prepare by selecting potential evacuation sites and checking wind direction, anticipating the worst-case scenario.

Infrastructure damage caused by large-scale volcanic ashfall and specific countermeasures

If Mount Fuji erupts, a large amount of volcanic ash will fall on the Kanto region and surrounding areas, paralyzing transportation networks. The Cabinet Office guidelines indicate that the following effects may occur:

Specific details of the damage caused by large-scale ashfall

1. Suspension of rail and surface line operations
   • Even a small amount of ashfall will halt train operations. This is because railway safety standards are very strict.
   • Without alternative transportation options, people will be unable to travel, severely impacting commuting and logistics.
2. Decline in power supply
   • When it rains, if more than 3 cm of ash falls, it will become impossible to use the road even for tricycles.
   • When the humidity of the air increases, power lines lose their insulation properties, causing power outages (3mm or more).
   • This will particularly disrupt fuel supply at thermal power plants.
3. Road traffic restrictions
   • When ash falls to a depth of 10 cm or more during dry periods, even two-wheel drive vehicles become unable to drive.
   • Large trucks and buses will have difficulty traveling, which will have a serious impact on the logistics network.
4. Communication failure
   • Volcanic ash adhering to base station antennas can cause signal problems.
   • If the internet or mobile phones become unusable, implementing business continuity plans (BCPs) becomes difficult.
5. Water supply cutoff due to water quality deterioration
   • If volcanic ash flows into water sources, the supply of drinking water will be cut off.
   • The water supply system's filters may be clogged, potentially causing the water purifier to malfunction.
6. Air conditioning and electrical equipment malfunctions
   • Air conditioners and other outdoor units will malfunction if they become clogged with ash. This reduces their cooling capacity, rendering office equipment unusable.
   • Temperature control in the server room becomes difficult, leading to system shutdowns.

Temporal characteristics:
The eruption itself could last for several weeks, and recovery could take several months. Be aware of the risk that the Tokyo metropolitan area could become an isolated island, unable to function for an extended period.

Preparatory actions that companies and individuals should actually take

1. Selection and confirmation of evacuation routes
   • We should establish a guideline: "If the alert level for Mount Fuji's eruption reaches level 3, leave Tokyo."
   • Prepare multiple potential locations and confirm a safe place considering the wind direction.
2. Setting up work-from-home triggers
   • Establish a specific criterion: "Transition to home care when volcanic ash falls to X cm or more."
   • Establish rules for notifying employees (such as communication flows via chat tools or email).
3. Business Continuity Plan (BCP) Implementation and Development
   • Prioritize maintaining infrastructure such as systems for medical institutions.
   • Establish a remote backup system for the servers.
   • Prepare alternative means of communication (such as satellite phones).
4. Implementation of training and practical exercises
   • Takenaka Corporation learned about the difficulties of actual processing by creating an opportunity to "handle volcanic ash."
   • Canon MJ is implementing e-learning for all employees (60% have taken part). They also provide hands-on training for executives.
5. Strengthening inspections of infrastructure equipment
   • Perform maintenance to increase resistance to volcanic ash, such as regularly cleaning air conditioners and other HVAC equipment.
   • Critical areas such as server rooms will be kept strictly sealed and clean.

Supplementary information and points to change in your "work sensibilities"

Experts point out:
According to Osamu Yamaguchi of MS&AD InterRisk Research Institute, it is advisable to always establish criteria for "not coming to the office" and "triggers for sending employees home." This is because delays in decision-making during a disaster will prolong the recovery period. Responding without preparation will result in significant time loss.
Another important point is that it is a disaster with little experience. In the case of a Mount Fuji eruption, there is little historical data on damage, so there is a high possibility of facing unforeseen circumstances. "An attitude of 'preparing for the worst and not being afraid of a false alarm' is required" (words of Canon's Crisis Management Division Manager).

1. A "renewal of our perception" of disasters is necessary.
   • Unlike earthquakes or floods, volcanic ashfall cannot be judged based on past experience. We need to abandon the notion that "volcanic ashfall equals normal conditions."
   • IT companies, in particular, rely heavily on communication infrastructure, so it's crucial to have alternative means such as satellite connections.
2. Business Continuity Planning (BCP) tends to become mere theoretical speculation.
   • Mr. Sugiuchi of Takenaka Corporation says, "We start by learning the basics." There's no point in creating a plan without the necessary knowledge.
   • Simulations that simulate actual ashfall conditions and on-site training are necessary.
3. Compared to other projects, it tends to be "put on the back burner."
   • With global issues such as geopolitical risks and tariff problems receiving more attention, awareness of local disasters like the eruption of Mount Fuji tends to fade.
   • However, because the impact is concentrated in the Tokyo metropolitan area, the damage will be immense. It would be dangerous to put this on the back burner as a priority.
4. Employee training and psychological preparation
   • It's important to understand that emotions tend to run high during disasters. Often, people can't act according to the manual.
   • Training such as e-learning and role-playing should be used to cultivate the ability to remain calm and composed even under stress.
5. Collaboration with external support is also important.
   • Establishing cooperative relationships with local governments and disaster prevention companies will expedite information sharing. It's also necessary to be prepared to hire specialized companies for tasks such as volcanic ash removal.

Column: Changes and Outlook from 2025 Onward
In March 2025, after the Cabinet Office formulated guidelines, the Tokyo Metropolitan Government also released a video illustrating its projected impacts. This has gradually spread risk awareness within the business community, but currently, it is still rare for companies to decide on "concrete actions."
However, investing in disaster preparedness is considered to have a high return on investment (ROI) in the sense that it "reduces future damage costs." In many cases, the costs of neglecting preparedness are far greater.

Summary: Let's consider the essence of risk management in the workplace.

Why are so many companies not preparing for an unprecedented disaster like a Mount Fuji eruption? The main reasons are the uncertainty surrounding the potential damage and the unpredictability of when it might occur. However, this isn't just anxiety; it's a fundamental challenge in risk management.

1. 1. The attitude of "preparing for the worst-case scenario" is important.
      • Delays in the initial response to a disaster will exacerbate the damage. Minimizing losses can be achieved by early determination of evacuation routes and establishment of criteria for working from home.
   2. A "BCP" (Business Continuity Plan) requires practical training, not just a manual.
      • Instead of leaving it as mere theoretical speculation, it's necessary to repeatedly conduct simulations of "how it actually works" and on-site work training.
   3. "Awareness of disasters" should be instilled as part of the organizational culture.
      • Disaster preparedness awareness needs to be shared not only among individuals but among all employees. We will accumulate knowledge and experience through e-learning, practical training, and other means.
   4. Because it is an unprecedented disaster, we must continue to learn.
      • It is necessary to not only learn from past cases, but also to utilize the latest research findings (such as guidelines from the Cabinet Office and videos from local governments).
   5. View "preparation" as an investment, not a cost.
      • Considering the costs of recovery after a disaster and the loss of revenue due to business closures, preventative investment is extremely efficient. Waiting around because "it'll be a hassle later" is a significant risk.

If you want to apply these points to your work, the principle that **"the greater the uncertainty, the more reassuring it is to plan ahead"** comes into play. Especially in business, how quickly you can resolve "unforeseen circumstances" is crucial to a company's survival and growth. Local disasters like the eruption of Mount Fuji are a significant issue, on par with "geopolitical risks," because the impact is concentrated in the Tokyo metropolitan area.

Conclusion:
Because we don't know when Mount Fuji will erupt, it's crucial to take three actions: prepare for the worst-case scenario, establish initial response criteria, and conduct repeated on-site training.
Only well-prepared companies can withstand disasters and ensure business continuity. The ability to manage uncertainty is essential in both work and organizational management.