Earthquakes can be mitigated by dredging canals and rivers — PM Tarique Rahman's claim is misleading

What was claimed?

On Wednesday, 20 May 2026, at the foundation stone laying ceremony of the National Disaster Management Research and Training Institute at Satais Dhorpara in Tongi, Gazipur, Prime Minister Tarique Rahman said:

"Canals and rivers have a relationship with earthquakes. So we must take effective preparations now to deal with the disaster."

Daily Samakal later headlined this statement as "Earthquakes must be dealt with through canal and river dredging: Prime Minister" and circulated it as a social-media card. In the same speech, the PM also discussed three issues together — the danger of excessive groundwater use, food production demand, and disaster risk. The proposed institute, built at a cost of approximately Tk 5.4 billion, is scheduled for completion by 30 June 2028.

The verdict: Misleading — why?

Let's look at the problems with the PM's statement one by one.

1. What actually causes an earthquake?

Knowing the answer to this question alone reveals the error in the claim. According to the simple explanation from the US Geological Survey, the Earth's outer shell is broken up into several massive pieces called tectonic plates. These plates move a few millimetres each year. But at their edges — at fault lines — two plates rub against each other. Friction holds them stuck, energy builds up. Eventually the friction gives way and the plates suddenly slip past each other. That sudden slip is what we feel as an earthquake.

Bangladesh's earthquake risk comes from the collision of three of these plates — the Indian, Eurasian, and Burma plates. Active faults like the Dauki Fault near Sylhet and the Madhupur Fault near Mymensingh are still moving by a few millimetres every year ^[1][2].

Now the question: how deep does canal or river dredging go? A few metres at most. And how deep do earthquakes happen? Anywhere from a few kilometres to over a hundred kilometres below the surface. The Earth's lithosphere — the rigid outer shell — alone is about 100 km thick. The idea that digging a few metres deep on the surface can stop plate movement happening kilometres below is scientifically impossible. It's a bit like trying to change the Moon's orbit by pouring water on your roof.

2. No scientific authority in the world endorses this method

International bodies that decide what works in earthquake mitigation — the UN Office for Disaster Risk Reduction (UNDRR), the US Federal Emergency Management Agency (FEMA), USGS, and Bangladesh's own National Building Code 2020 (BNBC 2020) — all list the same measures: stricter building construction, retrofitting old buildings, restricting construction in risky areas, and keeping people prepared ^[3][4]. Nowhere — not in a single one — is "canal dredging" or "river dredging" listed as a method.

Even Bangladesh's own researchers, when they publish papers on earthquake risk, talk about Sylhet-Mymensingh faults, Dhaka's soil composition, building quality — never canal or river dredging.

3. Soil liquefaction — what the PM perhaps meant

There is a little bit of science that might lie behind the PM's statement. During an earthquake, a dangerous phenomenon called soil liquefaction can occur — saturated soft sandy soil behaves like a liquid under seismic shaking, causing buildings to tilt and collapse. Dhaka is at high risk because many neighbourhoods were built on filled-in lakes and ponds.

But science says the actual way to reduce liquefaction is the opposite of what the PM proposed. According to a 2025 study published in ScienceDirect, reducing liquefaction risk requires lowering the groundwater table, improving site-specific drainage, and conducting proper soil testing before construction ^[5]. Dredging canals and rivers actually increases groundwater recharge — meaning groundwater levels rise — which can increase rather than decrease liquefaction risk.

Also, the 2019 study that linked Dhaka's water bodies to earthquake vulnerability was specifically about filled-in urban lakes and ponds — not rural irrigation canals. The PM's programme is the nationwide re-excavation of 20,000 km of rural canals and rivers over the next four years — a completely different context.

4. Some research even suggests the opposite — reducing water may increase earthquakes

A 2016 study reported by the Kathmandu Post suggested that the massive groundwater extraction in the Indo-Gangetic Plain (across India, Pakistan, and Bangladesh) may have contributed to the severity of the 2015 Nepal earthquake ^[6]. In other words: reducing water may increase earthquakes. No research in the world claims the opposite — that adding water reduces earthquakes. What the PM said actually contradicts even this hypothesis (which itself is contested).

So what actually works for earthquake mitigation?

On this question, the world's earth scientists, engineers, and disaster management experts have long reached a consensus. Earthquakes cannot be prevented — but we can prepare so that buildings don't fall during one, and even if they do, people don't die. According to Bangladesh's Ministry of Housing and Public Works, proper implementation of this preparation can reduce the risk of earthquake-related building collapse in Dhaka by up to 40% ^[3].

1. Following the Building Code (BNBC 2020)

Bangladesh has its own building construction law — the Bangladesh National Building Code 2020, or BNBC 2020 for short. This law divides the country into four earthquake-risk zones — Sylhet is the highest risk, the southwest is the lowest. For each zone, the code specifies how buildings must be constructed — pile depth, amount of steel rebar, concrete quality, all of it. The problem is — the code exists, but there are few inspectors to check whether it's being followed. The Bangladesh Building Regulatory Authority (BBRA) Act, passed on 10 April 2026, is expected to strengthen this oversight.

2. Retrofitting old vulnerable buildings

Many of Dhaka's buildings were built before the building code existed — buildings that are 30 to 40 years old. These will be the first to collapse in an earthquake. The only solution is 'retrofitting' — strengthening columns and beams in old buildings, adding cross-bracing, reinforcing foundations. It's expensive work, but much cheaper than tearing down and rebuilding the whole structure. Japan, Italy, and Turkey have all invested heavily in this.

3. Base isolation for major structures

Base isolation is an engineering technique where a building or bridge is set on spring-like or rubber-pendulum bearings that partially decouple it from the ground. So when the ground shakes during an earthquake, the structure on top shakes much less. Bangladesh's Padma Bridge and Jamuna Bridge both use this technology — the Padma Bridge has double concave friction pendulum bearings, the Jamuna Bridge has seismic steel pintles. This technology should be made mandatory for critical infrastructure.

4. Restricting construction in liquefaction-prone areas

Parts of Dhaka, Narayanganj, and Gazipur sit on soil that is liquefaction-prone — especially areas built on filled-in ponds, lakes, or old river beds. Tall buildings in these areas need deep soil testing, special foundation design, and strict inspection before construction. In some cases, heavy buildings should simply be banned in these zones.

5. Public awareness and regular drills

After Chile's 1960 magnitude 9.5 earthquake, the country brought in strict building codes. When an 8.8 magnitude earthquake struck in 2010, the damage was far smaller. In Japan, schoolchildren practice earthquake drills every month — where to hide, where to stand, how to evacuate. Bangladesh needs the same kind of regular drills and public-awareness campaigns. The government's new disaster management institute is a positive step in this direction.

What was the PM actually trying to say?

This is also worth understanding. In his full speech, the PM brought three things together — the crisis of excessive groundwater use, the need to meet food production demand, and disaster risk reduction. The canal/river dredging programme is genuinely valuable for water resource management, agriculture, flood control, and environmental balance — no one disputes that. It will provide irrigation water, hold floodwater, and reduce pressure on groundwater.

But presenting this programme as an earthquake mitigation strategy is scientifically incorrect. Earthquakes and floods/waterlogging/drought are completely different kinds of disasters. A solution for one is not a solution for the other.

The PM himself acknowledged in the speech that "natural disasters cannot be stopped" — which is correct. But by linking canal and river dredging to earthquake response, he risks creating the impression in his audience that dredging will reduce earthquake damage. Science says it will not.

The risk of misinformation from a head of state

Bangladesh is a country at high earthquake risk. Sylhet, Mymensingh, and Kishorganj are particularly vulnerable. Outlets including The Business Standard have warned for years about the catastrophic damage a magnitude 7+ earthquake could cause ^[7]. Experts estimate that such an earthquake could damage hundreds of thousands of buildings in Dhaka alone.

In this reality, the government's earthquake policy should focus on strict BNBC 2020 enforcement, retrofitting risky old buildings, and large-scale public awareness. Canal and river dredging is a separate and independently valuable programme — but presenting it as part of earthquake preparedness risks distracting the public from the real preparation work: building codes and structural safety.

When a head of government makes a scientifically weak claim, it spreads quickly among the public and remains a belief for years. On a subject like earthquakes — where wrong preparation means lost lives — knowing and communicating the correct science is part of the head of state's responsibility.

Conclusion

The simplified claim that "earthquakes can be mitigated by dredging canals and rivers" — as expressed by Prime Minister Tarique Rahman — is not supported by science. No earth science authority or disaster management agency in the world recognises this as an earthquake mitigation strategy. Earthquakes are caused by the collision of tectonic plates deep beneath the Earth's crust — a few metres of surface excavation cannot change this process. The methods that actually work to reduce earthquake damage — building codes, retrofitting, base isolation, public awareness — are a completely different kind of preparation. The claim is therefore misleading.