An office stockpiling plan to prepare for a Nankai Trough earthquake | How to think about food stockpiling

April 7, 2026April 10, 2026

Summary of this article

A Nankai Trough earthquake has a 70–80% probability of occurring within the next 30 years, and restoring electricity is said to take 7 days, water 30 days, and gas 60 days. For 50 employees over 7 days, about 1,200 meals are needed, with a guideline ratio of 40% staples, 20% soups, 25% side dishes, 10% supplementary food, and 5% special-diet items. We explain securing 3 liters of water per person per day, preparing a portable gas stove, and an approach to long-term stockpiling that makes use of dried vegetables.

TOC

What you will learn from this article

Projected Damage from a Nankai Trough Earthquake and the Need for Office Stockpiling
How to Calculate Stockpile Amounts Based on Cabinet Office Guidelines
Specific Items and Quantities of Food Stockpiling for a Prolonged Evacuation
How the Rolling Stock System Works and Points for Running It
How to Stockpile as Much as Possible with Limited Budget and Space

“If a Nankai Trough earthquake hits, how many days would our office’s stockpile last?”

Honestly, I don’t think many disaster-preparedness managers can answer this question on the spot.

The Cabinet Office projects the probability of a massive Nankai Trough earthquake at 70–80% within the next 30 years. In the worst case, figures of more than 320,000 deaths and 2.38 million fully collapsed buildings have been published. And restoring lifelines is said to take 7 days for electricity, 30 days for water, and 60 days for gas.

In other words, if employees are stranded at the office, you have to be prepared for a stay of several days to more than a week. What do you do for food during that time?

This article explains how to build an office food stockpiling plan from scratch, with a specific Nankai Trough earthquake scenario in mind.

Correctly Understanding the Projected Damage from a Nankai Trough Earthquake

Projected Scale of Damage and Range of Impact

A Nankai Trough earthquake is projected to bring shaking of seismic intensity upper-6 to 7 across a wide area from Shizuoka to Miyazaki Prefecture.

The fact that damage extends over a wide area is what decisively distinguishes it from other earthquakes. With a Tokyo inland earthquake, support from outside the Kanto region arrives relatively quickly, but the Nankai Trough hits a wide range of the Pacific coast at once, so relief supplies take time to reach you.

Item	Tokyo Inland Earthquake	Massive Nankai Trough Earthquake
Projected seismic intensity	7 (localized)	Upper-6 to 7 (wide area)
Projected deaths	Up to 23,000	Up to 323,000
Range of impact	Centered on the Tokyo metropolitan area	30 prefectures on the Pacific side
Lifeline restoration	Electricity 7 days / water 30 days	Electricity 7 days / water 30 days / gas 60 days
Arrival of relief supplies	Relatively fast	High risk of delay due to wide-area damage
Number of stranded commuters	About 8 million	Hard to estimate (wide area)

The row to pay attention to here is “arrival of relief supplies.” In a wide-area disaster, municipal stockpiles are also limited, and distribution to businesses tends to be put off.

The Reality That “3 Days’ Worth” Is Not Enough

You’ve probably heard that “office stockpiles should be 3 days’ worth.” This is the minimum standard set by Tokyo’s ordinance on measures for stranded commuters.

But in the case of a Nankai Trough earthquake, is 3 days’ worth really enough?

The Cabinet Office’s “Basic Plan for Promoting Disaster-Prevention Measures for the Nankai Trough Earthquake” recommends at least one week’s worth of stockpiles for households. For offices too, 3 days is only the bare minimum. Considering the risk of severed logistics, 5 to 7 days’ worth of stockpiles is a realistic line.

Days of stockpile	Scenarios covered	Risk
For 3 days	Tokyo inland or localized earthquake	Insufficient for a wide-area disaster
5 days’ worth	Medium-scale wide-area disaster	Worrying if logistics delays drag on
7 days’ worth	Nankai Trough–class wide-area disaster	A minimum line of reassurance
10 days’ worth	Worst-case scenario	Trade-off with space and cost

A Simulation of a Quake Striking During Work Hours

Let’s consider a quake striking during the daytime on a weekday.

If all employees in the office start heading home at once, the risk of secondary disasters rises. From the lessons of the 2011 Great East Japan Earthquake, the principle is “don’t move around needlessly.”

If the office is structurally safe, staying put is the right answer. But that assumes the office has enough food and water.

Assuming an office of 50 employees for a 7-day stay, the food needed is 50 people × 3 meals × 7 days = 1,050 meals’ worth. That’s quite a lot, isn’t it?

How to Calculate Stockpile Amounts and Specific Items

The Basic Formula

Calculate the stockpile amount with the following formula.

Required stockpile = number of employees × meals per day × days of stockpile

It is recommended to add a 10–20% margin here for visitors and nearby residents.

Here’s a concrete example.

Condition	Calculation
Number of employees	50 people
Meals per day	3 meals (breakfast, lunch, dinner)
Days of stockpile	7 days
Base stockpile	50 × 3 × 7 = 1,050 meals
Margin (+15%)	1,050 × 1.15 ≈ 1,208 meals
Required stockpile	About 1,200 meals

Water is a guideline of 3 liters per person per day. 50 people × 3 liters × 7 days = 1,050 liters. That’s 525 two-liter bottles.

Stockpile Item List by Category

What foods do you gather for 1,200 meals? Think about it from both nutritional balance and stress care.

Category	Example items	Guideline ratio	Notes
Staples	Alpha rice, crackers, canned bread	40%	Energy source. Use several types so you don’t tire of them
Soups	Dried-vegetable soup, miso soup, instant soup	20%	A warm meal is an emotional support
Side Dish	Canned goods (tuna, mackerel, yakitori), retort curry	25%	Securing protein
Supplementary food and snacks	Nutritional supplement food, chocolate, nuts	10%	Energy replenishment from sugars and fats
Special-diet items	Allergy-friendly food, halal food	5%	To match your workforce composition

What’s easy to overlook is the importance of “soups.”

In a disaster, when dry meals go on and on, it wears on you mentally. Just one cup of warm soup changes how you feel entirely. Even at shelters after the Great East Japan Earthquake, many reported “bursting into tears when I could get a warm soup.”

Agriture’s dried vegetables turn into a nutritious soup just by pouring hot water. They keep for a long time and don’t take up much room, so they fit even in an office’s limited stockpiling space. I think the value of dried vegetables as disaster stockpiles deserves to be more widely known.

Securing Water and Means of Cooking

Just as important as food are water and a means of heating.

Stockpile item	Required amount (50 people, 7 days)	Storage space guideline
Drinking water	525 two-liter bottles	About 2.5 square meters (3 pallets’ worth)
Cassette stove	3–5 units	30 or more gas canisters
Paper cups and paper plates	1,200 of each	About 2 cardboard boxes
Plastic wrap	10 rolls	Lay it on plates to cut down on washing up

Assuming electricity is out, a portable gas stove is essential. Whether or not you can boil water greatly changes the range of what you can eat. Both alpha rice and dried-vegetable soup show their true worth only with hot water.

How to Choose Foods Suited to Long-Term Storage

Don’t Choose by Best-Before Date Alone

When choosing disaster stockpile foods, it’s easy to focus only on the length of the best-before date. But what really matters is the balance of the following four points.

Selection criterion	Points to prioritize
Best-before date	3 years or more is ideal. Assuming rolling stock, even 1 year is fine
Ease of Preparation	Prioritize items that are ready with just water or hot water
Nutritional balance	Not just staples, but sources of vitamins and minerals too
Ease of eating	Something you can still stomach even under stress

Even for a stockpile food with 5-year storage, it’s better to avoid foods you’ve never actually eaten. In a disaster, “something you’re eating for the first time” is a high psychological hurdle.

Why Dried Vegetables Are Excellent as Stockpile Food

Frankly, dried vegetables are a food that deserves far more use as disaster stockpiles.

Comparison item	Dried vegetables	Canned goods	Retort foods	Freeze-dried
Weight	Very light	Heavy	Somewhat heavy	Light
Storage space	Small	Large	Moderate	Small
Best-before date	6 months to 1 year	3–5 years	1–3 years	3–5 years
Nutritional value	Rich in vitamins and dietary fiber	Somewhat reduced by processing	Tends to have more additives	Relatively retained
Preparation Method	Just pour hot water	Can be eaten as is	Warming in hot water is ideal	Pour hot water
Cost	Low to medium	Low	Medium	Medium to high

The greatest strengths of dried vegetables are their lightness and space-saving. Compared with fresh vegetables of the same nutritional value, the weight is about one-tenth.

The best-before date is shorter than canned goods, but with a rolling stock system there’s no problem. In fact, “regularly consuming and replacing” has the benefit of always keeping them fresh.

Handling Allergies, Religion, and Vegetarian Needs

What you must not forget is accommodating a variety of dietary restrictions.

If even one employee in an office of 50 has an allergy, a stockpile for that person is needed. Understand all employees’ dietary restrictions in advance and put them on a list.

Because dried vegetables are made from vegetables themselves, they are a food that is easy to accommodate for many allergies. Many products contain none of the specified raw materials such as wheat, milk, or egg, and they can also suit vegetarians and vegans.

Building a Rolling Stock System

What is rolling stock?

Leaving stockpile food “just sitting there” and discarding it once it passes its best-before date—that’s an enormous waste, isn’t it?

Rolling stock is a method of consuming stockpile food in everyday use and replenishing what you use. You maintain a constant amount of stockpile while preventing best-before dates from lapsing.

Method	Benefits	Cons
Bulk-purchase-and-replace method	Simple to manage	Risk of mass disposal when dates lapse
Rolling stock	Zero waste, always fresh	Needs rules for consumption and replenishment

Specific Operating Rules

Setting operating rules like the following makes it easy to keep up without strain.

Set a monthly check day

Inventory check on the 1st of every month
Move foods within 3 months of their best-before date to the “consume” list
Put the items to consume out in the break room for anyone to eat freely
Replenish what was eaten the following month

Rotating those in charge

Leaving it to a single disaster-preparedness manager makes it dependent on one person. A rotation of two or three people, with the checklist stored in a shared folder, is recommended.

Automating the ordering cycle

Setting up a system to order fixed quantities each quarter prevents “accidentally forgetting to order.” Agriture also offers a regular delivery plan for offices. With a system that delivers dried vegetables every 3 months, the effort of replenishment is nearly zero.

Linking with Tasting Events

Combining the consumption phase of rolling stock with an in-house tasting event is a two-birds-one-stone approach.

Raising disaster awareness
You can experience the taste of the stockpile food in advance
Energizing internal communication
Achieving zero waste

If you bill it as a “disaster-stockpile tasting party,” mere food consumption turns into an event. Holding it about twice a year as part of disaster drills is ideal.

How to Clear Budget and Space Constraints

Priorities Within a Limited Budget

You don’t need to gather everything at once. Set priorities and build it up in stages.

Priority	Item	Rough budget (for 50 people)	Days of stockpile
Top priority	Water, alpha rice, crackers	150,000–200,000 yen	For 3 days
Stage 2	Soup and miso soup, canned goods	100,000–150,000 yen	+2 days (5 days total)
Stage 3	Supplementary food, special-diet items	50,000–100,000 yen	+2 days (7 days total)
Additional	Cooking utensils, sanitary supplies	50,000–80,000 yen	–

First secure 3 days’ worth as the top priority, then expand to 7 days’ worth within six months. On this schedule, it can be achieved with an annual budget of 350,000–530,000 yen.

Ways to Manage Storage Space

“We don’t have space for stockpiles” is the most common complaint.

There is an approach called distributed stockpiling. Rather than concentrating everything in one place, you store it split across each floor and each department.

In desk drawers: one day’s worth per person
In meeting-room cabinets: two days’ worth shared per floor
In the warehouse: the remaining four days’ worth shared company-wide

Dried vegetables pair well with this distributed stockpiling. Being light and compact, they can be stored around desks without strain. The sense that 50 meals’ worth fits in a single cardboard box should be a relief for space-constrained urban offices.

Using Subsidies and Tax Incentives

There are subsidies and tax incentives you can use for disaster stockpiling.

Municipal disaster-stockpile subsidies (in Tokyo, part of the stockpiling cost is subsidized as a stranded-commuter measure)
Deductibility of disaster-related expenses
Subsidies tied to formulating a BCP (business continuity plan)

Programs differ by municipality, so try inquiring with your local disaster-prevention division. You may find more generous support than you expected.

Summary

A Nankai Trough earthquake is not a matter of “whether” it will happen, but “when.”

Office food stockpiling is the most basic measure for protecting employees’ lives and safety. Rather than the minimum line of 3 days’ worth, set a target of 7 days’ worth when building your plan.

What matters is not “making a perfect plan” but “taking the first step today.” First, 3 days’ worth of water and alpha rice. Next, 5 days’ worth with dried-vegetable soup and canned goods. Build it up in stages and it fits within a realistic range of budget and space.

Agriture’s dried vegetables are lightweight, space-saving, and long-storing, making them ideal for the soup category of disaster stockpiles. Since you can use them in everyday cooking with rolling stock, there’s no wasteful disposal. If you’re considering a review of your stockpile plan, do add them as one of your options.

FAQ

Q1: Is office disaster stockpiling required by law?

It is not a nationwide obligation, but in Tokyo the ordinance on measures for stranded commuters sets a 3-day stockpile per employee as an effort obligation for businesses. Other municipalities are increasingly enacting similar ordinances. Even without a legal obligation, stockpiling should be regarded as a corporate responsibility as part of a BCP (business continuity plan).

Q2: How can I efficiently manage the best-before dates of stockpile food?

The basics are to create an inventory table in Excel or Google Sheets, recording items, quantities, best-before dates, and storage locations. Setting up alerts three months before expiry helps prevent dates from lapsing. Introducing rolling stock greatly reduces the management effort.

Q3: In a Nankai Trough earthquake, which areas is stockpiling especially important?

Shizuoka, Aichi, Mie, Wakayama, and Kochi Prefectures are projected for seismic intensity 7 and are especially important. However, the Kinki region—Osaka, Kyoto, Hyogo, and so on—is also projected for lower-6 to upper-6, so it is not just a Pacific-side issue. Because damage to logistics hubs affects inland areas too, preparation is needed nationwide.

Q4: Are there alternatives if water stockpiling takes up too much space?

Alternatives include installing a water server (a type usable during power outages), stockpiling water purifiers, and setting up rainwater tanks. You can also apply an allocation trick: secure a minimum of drinking water while keeping more of the foods that need little cooking water (such as canned goods that can be eaten as is).

Q5: Is distributing stockpile food to employees for each to store effective?

Distributing one day’s worth per person is an effective method. As a compact disaster kit that can be kept at a desk, a set of 500 ml of water, a nutrition bar, and dried-vegetable soup is recommended. However, the rest of the stockpile should be centrally managed by the company. With personal storage alone, you get gaps in replenishment when people leave, and items get taken away.

Q6: How often should the stockpile plan be reviewed?

A review at least once a year—ideally every six months—is recommended. Disaster Prevention Day (September 1) and April at the start of the fiscal year are easy timings. Update it whenever there are changes, such as increases or decreases in headcount, office layout changes, or newly identified allergy information.

Author of this article

Rei Kojima Agriture CEO

CEO of Agriture Inc. Runs a contract processing and OEM business centered on dried vegetables and dried fruit. In partnership with farmers within Kyoto Prefecture, he pursues “sustainable food distribution” through the use of non-standard vegetables and support for sixth-industrialization. Drawing on extensive hands-on experience at manufacturing sites, he provides support that walks alongside every business considering OEM—from product planning and prototyping to small-lot handling, packaging design, and sales-channel development.