Mysterious gas stench worries geologists in Kanagawa Prefecture near the convergence of the Nankai Trough, Sagami Trough, and Suruga Trough, 3 extremely dangerous fault lines in Japan

Gas odor panicks geologists in Japan
Gas odor panicks geologists in Japan. Picture: Brian von der Brug / LA Times

At about 8:40 in the morning of Aug 21th, the Yokosuka Fire Department in Kanagawa Prefecture received 40 calls to their 119 emergency number all reporting a “smell of gas” in the area over the course of an hour.

Aside from the unpleasant smell, no one reported feeling ill from it either to the fire department or local hospitals.

This spate of reports is currently being looked into, but most are expecting the cause to be unknown. This is because the exact same situation has happened there twice before in as many months. In the early hours of July 17, emergency calls flooded in from Yokosuka and neighboring Miura City, and in the evening of June 4, about 260 calls were made to fire and police hotlines, all saying “it smells like gas.”

Since the hazards of a potential gas leak are nothing to take lightly, a thorough investigation was conducted following each round of reports, but no gas lines were found to be damaged, and the cause was officially unknown.

Readers of the news were also at a loss to pinpoint the cause of what’s happening in the area. Here some of their comments:

It’s happening every month, and they still can’t figure it out?

What is it? Methane?

That unsettling. Maybe there’s a natural gas field around there.

I remember experiencing a strange smell like that when walking to school. One day I discovered it was a pile of rotting onions. I wonder if the bad weather had made some farmers abandon their crops.

This is like in disaster movies when strange phenomenon begins before the real bad stuff starts.

I live across the harbor from Yokosuka and never smelled anything. But I’m sure people are going to start saying this is a sign of an earthquake.

Signs of earthquake?

Turns out, seismologist Manabu Takahashi at Ritsumeikan University was way ahead of that last comment and issued his warning right after the first smell incident. For a long time he has been studying the relationship between odors and earthquakes, based on research that found a distinct smell was created by rocks just before they break under stress.

Takahashi explains that large earthquakes don’t occur suddenly, rather they build up gradually over months, with the grinding tectonic plates slowly peeling away at each other before the main shock occurs. The professor worries that this process is what’s generating the widespread smells in the Yokosuka area.

Indeed, Yokosuka is located near the convergence of the Nankai Trough, Sagami Trough, and Suruga Trough fault lines (those three really big lines in the ocean).

Overview of Holocene Tsunami Deposits along the Nankai, Suruga, and Sagami Troughs, Southwest Japan
Overview of Holocene Tsunami Deposits along the Nankai, Suruga, and Sagami Troughs, Southwest Japan. Map: Researchgate

Prior to the 2010 Christchurch Earthquake in New Zealand and 1995 Hanshin Earthquake there had also been reports of unusual smells that were hard to describe but often compared to sulfur or burning rubber.

However, echoing the cynicism of the last comment, warnings that “the big one” is about to hit parts of Japan generally come about once a week, so this too should probably be taken with a grain of salt. After all, there’s no shortage of things in the world that create offensive odors, such as Tokyo Bay, which has recently come under fire for its high levels of fecal matter and bacteria, and is located right next to Yokosuka.

nankai trough earthquake map, nankai trough earthquake risk map, nankai trough earthquake threat map
Nankai Trough earthquake risk map

But it’s always a good idea to be prepared for natural disasters when living in Japan, no matter where you are or how it smells on any given day.

More earthquake news on Strange Sounds and Steve QuayleNow if you are looking for supplements to increase your healthy lifestyle and sexlife please visit Natural Health Source. Thank you for your support! [Asahi ShimbunNCBIYahoo! News/News Post SevenHachima Kiko, Japan Times]

Follow us: Facebook and Twitter. By the way you can also support us on PaypalPlease and thank you!


  1. Now if you buy a house you must make sure it will not sink hole in. You must spent more money to check it. Sink holes opens up all over world. Planet earth is dying within and without?

  2. The smell of gas so rampant is really telling you something. Very scary since a spark can ignite the whole area.

    I would be very afraid and cautious.

  3. It can’t be methane as that has no color or odor…..the rotten egg sulfur smell is added by industry to help identify leaks.

    • i was thinking hydrogen sulfide (H2S). This particularly pungent gas smells like rotten eggs and is often released from the earth near hot springs volcanic and earthquake prone areas.

    • You are correct, they add ethyl mercaptan to LP and natural gas to give it that rotten egg smell that is easy to identify.

      Perhaps they are smelling sulphur which occurs in volcanic regions ?

Leave a reply

Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.