While the last time Mount Fuji erupted was in 1707, the towering giant is still an active volcano.

Since the previous eruption more than 300 years ago, the volcano occasionally goes through periods of activity that can produce several hundred tremors a month, reported Reuters.

Recently, users on social media expressed their concern over "unusual behaviour" exhibited by the volcano.

Weather gets colder but Mount Fuji not covered with snow

According to various tweets on Mount Fuji taken in the last two weeks, netizens in Japan showed concern over the lack of snow on Mount Fuji, even despite cold weather at this time of the year.

This might be what most people expect Mount Fuji to look like during winter:

雪のある富士山が恋し過ぎる😭🗻#新富士山景 #癒しの富士 pic.twitter.com/9IkIleHHrb

— とにかく凄い富士山撮る人🗻橋向 真 (@MakotoHashimuki) December 22, 2020

This was taken last November:

去年の１１月はこんなに雪が積もっていたのに🗻
この日は地表に雪がなくて高所には積もる撮りやすい状態でした😌
2019/11#富士山 #mtfuji pic.twitter.com/4AlTki3CtP

— Taiki @富士山写真 (@tanasan02) December 22, 2020

The iconic snow cap is also what makes December one of the best months to observe Mount Fuji. Here's what Live Japan describes on their website:

"Mount Fuji during winter is stunningly beautiful, coated in pure white snow, and visible even from far away thanks to the dry air."

However, this is what residents in Japan observed this year:

今の富士山
今年はほんとに雪がない
春から様子がおかしい
ずっと pic.twitter.com/nfaf5f4imy

— ののそら (@59axN) December 21, 2020

日に日に雪がなくなっていく富士山を再び見にきた。#イマフジ pic.twitter.com/DTGfX77qxt

— 富士山写真家 オイ (@fujitomo_oi) December 22, 2020

Likewise, Twitter user @unananan expressed worry over the lack of snow:

This is Mt. Fuji today ... Mt. Fuji in December ...? Why isn't it snowing ...! ?? Strange........

これ·····今日の富士山ですよ············12月の富士山ですよ········？なんで雪ないねん······！？おかしい··········· pic.twitter.com/m8pME0suNm

— うなななん (@unananan) December 20, 2020

Replying to @unananan's tweet, another user @hiroapiii wondered if it was a sign of a possible eruption.

Some shared tweets of Mount Fuji without its snow-capped peak in the past week, with one user, @SumireSy, wondering if the temperature of Mt. Fuji is increasing.

The user added:

If it erupts, it’s dangerous.

綺麗な富士山🗻
いつもなら雪化粧されてる頃なのに
今年は雪化粧されてなくて不気味…
富士山の温度が高くなってるのかな
噴火しちゃったらやばい😱 https://t.co/FcSCMSlOtu

— ＿sumire＿ (@SumireSy) December 23, 2020

In a tweet by @shinry3, the mountain was covered with snow on Dec. 17, 2020, which has since melted.

4日前の17日の富士山です😊新幹線から撮ったもの。雪溶けちゃったんですね。 pic.twitter.com/jJ0Hnh4TEh

— ユウママ (@shinry3) December 21, 2020

Here's a bird's eye view of the volcano from the sky on Dec. 20 shared by Twitter user @asachan0913:

It seems like while Mount Fuji does not have its iconic snow cap, it has more snow on one side than the other.

An eruption could cause Japan S$32 billion dollars in damage

According to Japan Times, an eruption by Mount Fuji could cause up to ¥2.5 trillion (S$32 billion) in damage.

Public utilities, telecommunications and transport systems could be disrupted if that happens.

The eruption could also cause health problems, especially when the ash is inhaled.

While experts say the timing of the next eruption is unpredictable, Hiroki Kamata, a professor of volcanology at Kyoto University, feels that the situation is urgent.

Earlier this year, Kamata told Japan Times that “Mount Fuji is on standby for the next eruption", and cited that the volcano could be unstable after an earthquake that struck in 2011.

However, the director of the Center for Integrated Research and Education of Natural Hazards at Shizuoka University Takayoshi Iwata pointed out that eruptions may not always be correlated to earthquakes.

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Top image via @fujitomo_oi/Twitter and @tanasan02/Twitter