BJ Deming

Sakurajima 2024/2025 (Dec. 4, 2025, 1409 UTC)

Updates

For quite some time now, Sakurajima has been following this relatively quiet pattern, described again last week in the routine update (via Google Translate):

16:00, November 11, 2024, Fukuoka Regional Meteorological Observatory and Kagoshima Regional Meteorological Observatory

This is to inform you of the activity status of Sakurajima from November 8th to 15:00 on the 11th. There is a risk of an eruption accompanied by large volcanic rocks and small pyroclastic flows scattering more than 1 km from the Minami-dake summit crater and Showa crater.

Status of volcanic activity

Eruptive activity continues on Sakurajima.

Very small eruptions have occurred occasionally at the Minami-dake summit crater. In addition, fire reflections were observed at the crater at night using a high-sensitivity surveillance camera.

No eruptions or fire reflections have been observed at the Showa crater.

Volcanic earthquakes have been few and far between. No volcanic tremors have been observed.

Continuous GNSS observations have confirmed slight shrinkage on the baseline within Sakurajima since around January 2024, which is believed to be due to the contraction of the mountain. In addition, the baseline that sandwiches the Aira Caldera (inner Kagoshima Bay) has shown gradual expansion indicating long-term expansion deep underground in the Aira Caldera.
On Sakurajima, magma has been accumulating deep underground in the Aira Caldera (inner Kagoshima Bay) for a long time, and the amount of volcanic gas (sulfur dioxide) emitted is also generally high, so it is thought that eruptive activity will continue in the future. Please pay attention to future volcanic information…

I haven’t updated the 2023/2024 post since February.

Sakurajima does still have some spectacular vulcanian blasts, though, like this one —

— and given the slow inflation of Aira Caldera, as well as Sakurajima’s own occasional rounds of inflation, this volcano out in Kagoshima Bay will likely be a newsmaker next year, too.

🌋🌋🌋

Updates:

December 4, 2025, 6:09 a.m., Pacific: I am updating all these posts. Here is the current JMA update, via Google Translate:

Warning around the crater (volcanic alert level 3, mountain entry restrictions)

…

Current precautions, etc.

　Within approximately 2km of the Minami-dake summit crater and Showa crater, be on guard for large volcanic blocks and pyroclastic flows that will be scattered in a ballistic trajectory due to the eruption.

　On the downwind side, be careful as not only volcanic ash but also small volcanic blocks will be carried by the wind and fall far away. Be careful as large air vibrations caused by the explosion may shatter window glass.
Please also be aware that depending on future ash fall conditions, there is a possibility of debris flows occurring during rainfall.

Municipalities subject to eruption warnings

　In the following cities and towns, please be cautious and restrict mountain climbing around the crater.
　Kagoshima Prefecture: Kagoshima City

… Fukuoka Regional Meteorological Observatory and Kagoshima Regional Meteorological Observatory
Interpretive information on the status of the volcano
December 1, 2025, 16:00, Fukuoka Regional Meteorological Observatory and Kagoshima Regional Meteorological Observatory

　We would like to inform you of Sakurajima’s activity status from November 28th to 3:00 PM on December 1st. There is a risk of an eruption from the Minami-dake summit crater and Showa crater, accompanied by large volcanic blocks flying more than 1 km and small pyroclastic flows.

Volcanic activity status

　Volcanic activity continues at Sakurajima.
　
　Two eruptions occurred at the Minamidake summit crater during this period. Volcanic smoke rose up to 1,300 meters above the crater rim. Fire glare was also observed at the crater using a high-sensitivity surveillance camera at night throughout the period. No eruptions or fire glare were observed at the Showa crater.
　
　Volcanic earthquakes have been few. Volcanic tremors associated with eruptions have also occurred occasionally.
　
　Continuous GNSS observations have shown gradual expansion along the baseline between the Aira caldera (inner Kagoshima Bay) over a long period, indicating deep underground expansion of the Aira caldera.
　
　At Sakurajima, magma has been accumulating deep underground in the Aira caldera (inner Kagoshima Bay) for a long period, and volcanic gas (sulfur dioxide) emissions are generally high. Therefore, it is expected that eruptive activity will continue. Please pay close attention to future volcanic information…


　

November 17, 2025, 6:14 a.m., Pacific: Sakurajima had an impressive blast yesterday —

It looks to this layperson as though a lava dome blew up, as sometimes occurs at Mexico’s Popocatépetl.

— and it is still emitting some ash, but as Dr. Imura points out in the tweet and its linked article below, per X translation of the tweet, this activity is within the current alert level.

https://platform.twitter.com/widgets.js

August 20, 2025, 12:49 .m., Pacific: This is confirmed in today’s update. Alert level remains unchanged.

https://platform.twitter.com/widgets.js

X translation: “From around 16:00 on August 19 at Sakurajima (according to the Japan Meteorological Agency), the tilt variation showing an upward trend toward the summit continued in a state of equilibrium from around 10:00 to 13:00 on August 20, after which a gradual upward trend in tilt variation toward the summit resumed and is ongoing as of 21:29 on August 20.
On the Japan Volcanological Data Network (JVDN) website:
1st image: Tilt variation chart (tide-corrected) from August 18 to 21:29 on August 20
Japan Meteorological Agency Earthquake and Volcano Division Monitoring Section
Upper section: Sakurajima Amidagawa V.SFT2 N (lower side of the chart indicates north downward)
Lower section: Sakurajima Yokoyama V.SKA2 E (lower side of the chart indicates east downward)
2nd image: Observation point layout”

July 25, 2025, 12:44 a.m., Pacific: JMA repeated the remarks about expanding/not expanding, unlike last time, so I’m going to assume that some sort of expansion is ongoing; the sulfur dioxide emission is high, too.

Browser translation:

…Observations using inclinometers and extensometers on the island show that the mountain body continues to expand, but no particular changes are observed that indicate further expansion.
　
　Volcanic earthquakes have passed in a low state. Volcanic tremors associated with eruptions occasionally occurred.
　
　In the field survey conducted on the 23rd, the amount of volcanic gas (sulfur dioxide) released was extremely high at 4,700 tons per day (3,100 tons on the 16th last time)…

There’s a concept there that can be conveyed in Japanese but not in English.

July 22, 2025, 6:23 a.m., Pacific: Sakurajima might have stopped expanding, based on what translated into some confused wording in yesterday’s JMA update. It’s the same confusion that showed up in the English translation last time. Let’s wait and see.

July 18, 2025, 2:13 a.m., Pacific: JMA has been following the usual three-day schedule for updates, but they issued one today, just two days after the last one, noting that, after a recent (and typical) blast, “Observations using inclinometers and extensometers on the island indicate that the mountain continues to expand, and no significant contraction was observed due to yesterday’s eruption.”

That’s concerning, particularly when combined with a four-digit SO2 measurement this week.

July 11, 2025, 1:08 a.m., Pacific: Today’s JMA update still shows Sakurajima to be the activity focus around Aira caldera/northern Kagoshima Bay (Kirishima/Shinmoedake, just north of and outside Aira, is still with us but as far as they can tell through weather clouds, not doing much more than raising a relatively small plume):

Via Google Translate:

16:00, July 11, 2025, Fukuoka Regional Meteorological Observatory and Kagoshima Regional Meteorological Observatory

We would like to inform you of the activity status of Sakurajima from July 7th to 15:00 on the 11th. Sakurajima is in a state of mountain expansion. There is a risk of an eruption accompanied by large volcanic rocks and small pyroclastic flows that will fly more than 1 km from the Minami-dake summit crater and Showa crater. In addition, caution is required for ashfall on the downwind side.

Status of volcanic activity

Active volcanic activity continues on Sakurajima.

The mountain is in a state of mountain expansion. If an eruption occurs at the Minami-dake summit crater or Showa crater that relieves this mountain expansion all at once, there is a possibility of a large amount of ashfall, mainly on Sakurajima Island. Please use the ashfall forecast issued by the Japan Meteorological Agency to find out the area where ashfall and small volcanic rocks are expected to fall.

Six eruptions occurred at Minamidake summit crater, three of which were explosions. Smoke rose up to 1,800m above the crater rim. Large volcanic rocks were scattered in ballistic trajectories and reached as far as the 7th station (approximately 700m from Minamidake summit crater). Fire glare was also observed temporarily at night at the crater using a high-sensitivity surveillance camera.

No eruptions or fire glare were observed at Showa crater.

Volcanic earthquakes have been few and far between. Volcanic tremors occurred, mainly associated with eruptions.

On-site surveys conducted on the 7th and 9th revealed that the amount of volcanic gas (sulfur dioxide) emitted was extremely high, ranging from 2,700 to 4,000 tons per day (1,500 tons on the 2nd, the previous survey).

Continuous GNSS observations have shown gradual expansion over a long period of time along the baseline that borders the Aira Caldera (inner Kagoshima Bay), indicating deep underground expansion of the Aira Caldera.

At Sakurajima, magma has been accumulating deep underground in the Aira Caldera (inner Kagoshima Bay) for a long period of time, and the amount of volcanic gas (sulfur dioxide) emitted is generally high, so it is thought that eruptive activity will continue in the future. Please pay close attention to future volcanic information.

July 10, 2025, 1:14 a.m., Pacific: Per today’s update, the volcano continues to expand. Also, it exploded again today, per Tokyo VAAC, about an hour ago.

July 7, 2025, 6:42 a.m., Pacific: From today’s JMA update:

…Six eruptions have occurred at Minamidake summit crater. In the eruption that occurred yesterday (6th) at 9:33, smoke rose up to 3000m above the crater rim. In addition, fire reflections were observed at the crater at night using a high-sensitivity surveillance camera. No
　
　eruption or fire reflections have been observed at Showa crater.
　
　The mountain expansion that continued from around 5:00 on the 5th was slightly relieved by yesterday’s eruption and has since slowed down, but it has started to expand again from around 7:00 today (7th). If an eruption occurs at Minamidake summit crater or Showa crater that relieves this mountain expansion all at once, it may be accompanied by a large amount of ashfall, mainly on Sakurajima Island. Please use the ashfall forecast issued by the Japan Meteorological Agency to find out the areas where ashfall and small volcanic rocks are expected to fall.
　
　Volcanic earthquakes have been few and are continuing. Volcanic tremors have occurred due to the eruption…

I wish I could let go of the idea that Aira “wants” to have a Taisho-style eruption, couldn’t do it again easily at Sakurajima because of that open conduit, tried the Kirishimayama complex with on-again, off-again results, and now once more is focusing on Sakurajima, where it does have a known magmatic connection.

July 6, 2025, 3:04 a.m., Pacific: Yesterday morning (local time), JMA reports, Sakurajima began to expand. Today it has had two vulcanian blasts.

In today’s update, JMA notes that the expansion slowed down after the first eruption but did continue. I don’t know the status after the second eruption.

Please see my notes in the Shinmoedake/Kirishimayama post for some layperson speculation on Sakurajima, Aira, and Shinmoedake. That’s all it is — speculation from a layperson.

Dr. Imura probably wouldn’t subscribe to it. He recently tweeted that Sakurajima was conducting business as usual, and in another tweet, that Shinmoedake’s eruption is more serious, which even this layperson can see is true.

Now.

No one knows what the future holds, and still I like my very unscientific lay hypothesis about Aira perhaps “wanting” to put on a Taisho-style VEI 4, not being able to do so again at Sakurajima because of that volcano’s open conduit for much of the last seventy years, and so instead putting the squeeze on the Kirishimayama complex just outside Aira’s northern rim…or gas flux, or something else to fire up Kirishimayama which, unlike Sakurajima, has its own magmatic plumbing system.

The bottom line, though, as always, is correlation is not causation.

I’m just going to keep both posts pinned and hope that both volcanoes settle down. May many people earn their Master’s or Ph.D. later on by exploring potential Aira-Sakurajima-Shinmoedake 2025 interactions!

June 8, 2025, 3:25 a.m., Pacific: The last two JMA updates, at the usual three-day interval, have been similar to those before the recent uptick in activity, and they haven’t mentioned inflation of the edifice.

However, this tweet by a knowledgeable but unofficial source is an example of why I leave the post pinned — quieting down at a restless volcano does not always mean that it’s settling down:

X translation: “Japan Meteorological Agency Sakurajima volcano observation data as of 10 p.m. on June 7
● The increase in volcanic gas has been on a downward trend since its peak, and it is possible that new magma that has not yet degassed is rising.”

May 29,12:08 a.m., Pacific: Two VAAC advisories up: Sakurajima erupted about half an hour ago, with ash to, first, 6,000 and then 9,000 feet. That’s not very high.

No JMA updates yet. The volcano is partly visible on cams but the weather is cloudy and raining.

Edit: The current Zaiho Cam D shot is impressive because of weather and also shows that Sakurajima is fuming:

May 28, 2025, 5:53 p.m., Pacific: Sakurajima appeared quiet on the cams yesterday and overnight, plus there were no new Tokyo VAAC advisories on this volcano, so I didn’t check the JMA updates, not expecting another until the 29th.

The boffins snuck one in! I don’t know why, specifically, as it references just a few eruptions, as well as no explosions or notable seismicity, and the alert level is unchanged, but suspect it is because the edifice is still expanding.

This layperson understands that to be a sign that more violence — probably not plinian style, given the lack of intense precursors — may be possible in the future. The explosions on the 24th, which ashed central Kyushu, were not the final paroxysm. 😦

Here’s the relevant update text via Google Translate:

16:00, May 28, 2025, Fukuoka Regional Meteorological Observatory and Kagoshima Regional Meteorological Observatory

This is an update on Sakurajima’s activity from May 26 to 15:00 on May 28. There is a risk of an eruption accompanied by large volcanic rocks and small pyroclastic flows scattering more than 1 km from the Minami-dake summit crater and Showa crater.

Volcanic activity status

Eruptive activity continues on Sakurajima.

Very small eruptions have occurred occasionally at the Minami-dake summit crater. No explosions have occurred since the 24th.

No eruptions have been observed at the Showa crater.

Volcanic earthquakes have been few and far between. No volcanic tremors have been observed.

Observations using tiltmeters and extensometers installed on the island indicate that the mountain continues to expand.

Continuous GNSS observations have shown gradual expansion over a long period of time along the baseline that borders the Aira Caldera (inner Kagoshima Bay), indicating deep underground expansion of the Aira Caldera.

At Sakurajima, magma has been accumulating deep underground in the Aira Caldera (inner Kagoshima Bay) for a long period of time, and the amount of volcanic gas (sulfur dioxide) emitted is also generally high, so it is thought that eruptive activity will continue in the future. Please pay attention to future volcanic information…

May 26, 2025, 2:08 a.m., Pacific: JMA is back to three-day updates. Today they report only six eruptions since the 23rd but also note that Sakurajima continues to expand.

May 24, 2025, 4:44 p.m., Pacific: Sakurajima is doing something this morning in Japan —

— but it’s at a very low level.

JMA did not issue an update yesterday and there have been no new advisories posted at the Tokyo VAAC website since the 23rd (UTC).

This is good.

Could Sakurajima have had its climactic paroxysm for this cycle?

If so, given the volcano’s history, a lava flow is not inconceivable, but it probably would be small given the small size of those three explosions when compared to plinian-style activity.

We’ll find out more whenever JMA issues its next advisory — it might not be today, since they went at least three days in between updates before this crisis — or whenever Sakurajima gets angry again.

May 23, 2025, 6:41 a.m., Pacific: Per Tokyo VAAC advisories, several hours ago Sakurajima had three explosions in fairly close succession, with ash reported from 7,000 to 17,000 feet (nothing that would raise the alert level, but a high frequency).

Per this article (Japanese), ashfall is expected up the middle of Kyushu Island.

When it really gets going, Sakurajima is capable of ashing Tokyo, on the next big island to the north. Let’s hope we don’t see that.

In other news, Dr. Imura just tweeted that Showa crater was steaming.

https://platform.twitter.com/widgets.js

As noted in the updates, Showa has been quiet throughout this recent uptick in activity (and for quite some time before it, too).

? significance.

May 23, 2025, 12:38 a.m., Pacific: The volcano continues on, sometimes with low-level continuous ash emissions but more often with vulcanian bursts.

The largest of these recently occurred yesterday and Zaiho uploaded a video for it:

That’s impressive, but in terms of Sakurajima’s occasional plinian-style tantrums (last in 1914), it’s very low in intensity.

While on TalkWeather, I looked into how precursors of the 1914 Taisho VEI 4 eruption might compare to current activity, since the big concern, expressed by JMA and others, now is a possible repeat “big one” since the Aira reservoir is at its pre-1914 level.

Happily (in a layperson’s view), there’s no comparison. In the months leading up to the Taisho eruption, there was lots of seismicity, wells ran dry (from ground uplift), tide changes were noted at shores, and so forth.

This level of precursors would be picked up by (and might even swamp) current Sakurajima monitoring equipment. It is not present to that degree (but now you know why the boffins carefully mention earthquakes in their updates).

Too, there was no reported eruptive activity before Sakurajima cut loose on January 12, 1914, in a double-flank subplinian fissure eruption.

In contrast, the volcano now has been having vulcanian eruptions almost daily since 1955. This layperson wonders if the relatively open vent keeps pressure from building up to plinian levels.

Well, it has had a change in behavior recently, and though that’s just a mild uptick, Sakurajima must be watched very closely.

JMA is doing daily updates, and they were surprised to learn this week that sulfur dioxide emission had soared into five digits from that unusually low 300 reading.

This is usually emitted by degassing magma near the surface, but thus far there has been no matching increase in other signals reported, nor in activity.

Yet.

Here is JMA’s May 23rd update (via Google Translate):

Announcement by the Fukuoka Regional Meteorological Observatory and Kagoshima Regional Meteorological Observatory at 16:00 on May 23, 2025

This is an update on Sakurajima’s activity from May 19 to 15:00 on May 23. There is a risk of an eruption accompanied by large volcanic rocks and small pyroclastic flows that will fly more than 1 km from the Minami-dake summit crater and Showa crater.

Volcanic activity status

Active volcanic activity continues on Sakurajima.

At the Minami-dake summit crater, 82 eruptions occurred, 38 of which were explosions. In the explosion that occurred at 15:00 on the 20th, smoke rose up to 3,000 m above the crater rim. Large volcanic rocks were scattered in a ballistic trajectory and reached a maximum of the 5th station (about 1,200 m from the Minami-dake summit crater).

No eruptions have been observed at the Showa crater. Volcanic earthquakes have been few and far between. Volcanic tremors have mainly occurred, which are associated with eruptions. A field survey conducted yesterday (22nd) found that the amount of volcanic gas (sulfur dioxide) emitted was very high at 4,300 tons per day (11,200 tons on the 20th). Observations using tiltmeters and extensometers installed on the island indicate that the mountain continues to expand. Continuous GNSS observations have shown a gradual expansion over a long period of time along the baseline that sandwiches the Aira Caldera (inner Kagoshima Bay), indicating a deep underground expansion of the Aira Caldera. At Sakurajima, magma has been accumulating deep underground in the Aira Caldera (inner Kagoshima Bay) for a long period of time, and the amount of volcanic gas (sulfur dioxide) emitted is generally high, so it is thought that active eruptive activity will continue in the future. Please pay attention to future volcanic information…

May 19, 2025, 8:03 p.m., Pacific: This autotranslated news story sums up the activity: continued frequent explosions.

The mountain continues to hide from cam view behind clouds, but not from monitoring technology.

Level 3 alert continues, and per the May 19th JMA update, volcanic earthquake activity was up, in addition to tremors with each event.

Per Tokyo VAAC, the last blast was about an hour and a half ago, with ash up to 10,000 feet.

Here’s an unofficial graphic on the number of explosions between January 1 and May 19, 2025, along with plume height:

https://platform.twitter.com/widgets.js

May 16, 2025, 1:05 a.m., Pacific: Well, Sakurajima continues to have eruptive pulses, and per JMA, it is now expanding again.

Level 3 is maintained, and here is today’s update via Google Translate:

16:15, May 16, 2025, Fukuoka Regional Meteorological Observatory and Kagoshima Regional Meteorological Observatory

We would like to inform you of the activity status of Sakurajima from May 12th to 15:00 on the 16th. Sakurajima has been in a state of expansion. There is a risk of an eruption accompanied by large volcanic rocks and small pyroclastic flows that will fly more than 1 km from the Minami-dake summit crater and Showa crater. In addition, caution is required for ashfall on the downwind side.

Volcanic activity status

Active eruption activity continues on Sakurajima.

The mountain expansion that continued from around 20:00 on the 12th was temporarily contracted by the eruption from around 11:30 to around 15:30 yesterday, but it has resumed expansion and is continuing since then. There is a possibility of a large amount of ashfall in the future, mainly on Sakurajima Island. Please use the ashfall forecast issued by the Japan Meteorological Agency to check the areas where ashfall and small volcanic rocks are expected to fall.

There have been 10 eruptions and 7 explosions at the Minami-dake summit crater. The eruption that began at 10:45 yesterday (15th) continued until around 4:00 today (16th), with volcanic smoke rising up to 3,000m above the crater rim. Large volcanic rocks, which were scattered in a ballistic trajectory, reached as far as the 6th Station (approximately 1,200m from the Minami-dake summit crater). Eruptions have continued to occur intermittently since then.

There have been few volcanic earthquakes. Volcanic tremors have occurred, mainly associated with eruptions.

In field surveys conducted yesterday and today, large amounts of ashfall were confirmed, mainly on the eastern side of the island yesterday, and mainly on the northern side of the island today.

In a field survey conducted on the 12th, the amount of volcanic gas (sulfur dioxide) emitted was 300 tons per day (900 tons on the 2nd), which is somewhat low.

Continuous GNSS observations have shown a gradual expansion over a long period of time along the baseline that sandwiches the Aira Caldera (inner Kagoshima Bay), indicating a deep underground expansion of the Aira Caldera.

At Sakurajima, magma has been accumulating deep underground in the Aira Caldera (inner Kagoshima Bay) for a long period of time, and the amount of volcanic gas (sulfur dioxide) emitted is also generally high, so it is thought that eruptive activity will continue in the future. Please pay attention to future volcanic information.

The number of volcanic earthquakes and explosions is as follows. Note that the number of volcanic earthquakes is a preliminary figure and may be changed at a later date as a result of further investigation.

[Layperson speculation] That is an unusually low SO2 output for an erupting volcano. Combined with the expansion, I wonder if it means that a cap still exists somewhere in the plumbing. [/layperson speculation]

Here are some screenshots I grabbed from yesterday’s third eruption:

And here is a video Zaiho uploaded of one of the eruptions yesterday:

Finally, ashfall in Kagoshima City by a professor who says he is going to let the rain wash it off:

https://platform.twitter.com/widgets.js

May 14, 2025, 8:49 p.m., Pacific: Eruption #3 is ongoing, and the column is big but not plinian at this point. It is relatively low and responding to prevailing winds right now.

Sakurajima had erupted three times by 11:00 a.m. on the 15th, with smoke rising to heights of over 1,000 meters each time.

According to the meteorological observatory, Sakurajima erupted at 7:08 a.m. on the 15th, with smoke rising to a height of 1,000 meters from the crater.

Further eruptions occurred at 10:14 and 10:45 a.m., with ash plumes rising to 1,100 m and 1,300 m, respectively.

The eruption, which began at 10:45 a.m., is still ongoing, and by 11:15 a.m. the smoke had risen to 1,700 m from the crater…

_ Source (autotranslated)

May 14, 2025, 6:47 a.m., Pacific: Today’s update, via Google Translate — the alert level is unchanged, and if Sakurajima goes off, ashfall is expected mostly on the island:

Japan Meteorological Agency
Home > Information page for volcano climbers > Volcanic activity status
Status of volcanic activity (Sakurajima)

…

Municipalities subject to eruption warnings

　In the following cities and towns, please be cautious and restrict access to the mountain around the crater.

Kagoshima Prefecture: Kagoshima City

Volcanic eruption warnings and forecasts

…

16:00, May 14, 2025 Fukuoka Regional Meteorological Observatory and Kagoshima Regional Meteorological Observatory

Crustal movements indicating mountain expansion are being observed on Sakurajima. There is a risk of an eruption accompanied by large volcanic blocks scattering over 1 km from the Minami-dake summit crater and Showa crater, as well as small pyroclastic flows. In addition, caution is required for ashfall on the downwind side.

Volcanic activity status

On Sakurajima, crustal movements indicating the expansion of the mountain have been observed using tiltmeters and extensometers installed on the island since around 8 p.m. on the 12th. There have been no eruptions, including very small ones, since May 5th. If an eruption occurs at the Minami-dake summit crater or Showa crater that relieves this mountain expansion all at once, it may be accompanied by a large amount of ashfall, mainly on Sakurajima Island. Please use the ashfall forecast issued by the Japan Meteorological Agency to find out the areas where ashfall and small volcanic rocks are expected to fall.

Disaster prevention precautions, etc.

Within approximately 2 km of the Minami-dake summit crater and Showa crater, be on guard for large volcanic blocks and pyroclastic flows that will be scattered in a ballistic trajectory due to the eruption. Be careful on the downwind side, as not only volcanic ash but also small volcanic blocks will be carried by the wind and fall far away.

Be careful as there is a risk of window glass breaking due to large air vibrations caused by the explosion. Please be aware that depending on the future ashfall situation, there is a possibility of debris flows occurring during rainfall.

April 7, 2025, 5:13 a.m., Pacific: Per today’s JMA update, Sakurajima had 12 eruptions, eight of which were explosions. Level 3 alert is maintained.

While this is all still relatively low intensity, it is a change in behavior from those long-gone days of vulcanian blasts now and then.

If those could be compared to a hand slapping a volleyball, this layperson sees it now as a clenching fist, with arm muscles tightening for a blow.

This explosion below, some ten hours ago, will count on the next update. Note that the plume, while impressive, does not have the power yet to completely ignore prevailing winds and rise vertically.

Yet.

April 5, 2025, 5:29 a.m., Pacific:

https://platform.twitter.com/widgets.js

Tokyo VAAC’s initial advisory identified ash to 13,000 feet.

As impressive as this appears , and alarming for people nearby, it was not sustained. As of this writing, JMA has not added new information on the update page linked above.

April 5, 2025, 12:44 a.m., Pacific: From Japan’s public broadcaster:

https://platform.twitter.com/widgets.js

Per X translation of the tweet (link will be in Japanese), “On the evening of the 4th, an explosive eruption occurred on Sakurajima, bringing the total number of eruptions this year to 50, already exceeding the total for the whole of last year. The Meteorological Agency is calling for continued vigilance, as eruption activity is expected to continue.”

Per the current update, between March 31 and April 4, “Nine eruptions have occurred at the Minami-dake summit crater, four of which were explosions.” No deformation of Sakurajima is noted in the update, and they are maintaining the Level 3 alert.

March 27, 2025, 3:01 p.m., Pacific: There have been several explosions since the last blog update. This one occurred on March 25, but volcanologists haven’t updated their page, which is through the 24th. Level 3 still prevails.

February 10, 2025, 3:14 a.m., Pacific: Sakurajima, about fifteen hours ago — wow!:

JMA’s three-day update today includes that blast and is basically unchanged.

February 6, 2025, 11:12 p.m., Pacific: Yet another blast (and a majestic snowy Sakurajima, too! 😍):

On the live cam just now, though the day is cloudy, Sakurajima appears restless, too.

It continues to act differently from its more regular vulcanian pops of a few years ago, but no changes are noted in the update (current through the 7th). Whatever is going on is progressing at a geological rate, and we quick-timers will just have to continue waiting — aware of the fact that Aira (Sakurajima’s “daddy” underneath the north bay) is now at a similar stage of magma filling as it was in January 1914.

A hundred and eleven years later, volcanologists have this Decade Volcano monitored in many ways. If and when the volcano gets into a plinian mood again, it won’t be a surprise this time around.

But I hope old “Cherry Blossom Island” remains its iconic, rather quiet self for the remainder of our lives.

February 1, 2025, 10:32 p.m., Pacific: You don’t see this often from TROPOMI SO2, and the last time I saw such a notice (a while back), Sakurajima had a big explosive eruption several days later.

https://platform.twitter.com/widgets.js

At the moment, alert status and update (through January 31) are unchanged.

January 27, 2025, 11:04 p.m., Pacific: There are no major changes, but Sakurajima did have another explosion yesterday.

As well, there was a seismic swarm in the more active part of Aira Caldera. This is not unique, and that area has submarine fumaroles, etc., all the time — one nickname for that area is “bubbling” — but at least one, the M2.8, was felt in Kagoshima City.

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X translation: “Today, there was a swarm of earthquakes near Wakatakazu in the northern part of Kagoshima Bay, with a magnitude of M2.8 and a maximum seismic intensity of 2. Recently, similar observations were made around mid-December last year. The distribution of epicenters from December last year and a cross-section passing through Sakurajima. Until yesterday, data was provided by the Japan Meteorological Agency, and today it is provided by Hi-net seismic sources. The gray dots in the background represent deep low-frequency earthquakes since 2000.”

January 24, 2025, 3:30 a.m., Pacific: Per today’s update, they haven’t raised the alert but do note that activity is high.

Via Google Translate:

Status of volcanic activity

Sakurajima continues to experience active eruptive activity.
　
There were 10 eruptions at the Nandake summit crater, five of which were explosions. The plume rose to a maximum of 2500m above the crater rim. The large, ballistically scattered cinder reached a maximum of at the 7th station (about 900 m from the summit crater of Mt. Nandake).

Additionally, fire reflections were observed at the crater at night using highly sensitive surveillance cameras throughout the period.
　
No eruptions or fire reflections have been observed at Showa Crater.
　
Volcanic earthquakes have passed in a low state. Volcanic tremors occurred with the eruption.
　
In the field survey conducted on the 17th, no particular changes were observed in the geothermal area conditions on the southeast side of Mt. Minamidake or near the Showa crater compared to previous observations.
　
In a field survey conducted on the 20th, the amount of volcanic gas (sulfur dioxide) released was extremely high at 3,200 tons per day (2,300 tons on the 14th last time).
　
GNSS continued observations show a gradual elongation that indicates the expansion of the deep underground part of the Aira caldera over a long period of time at the baseline that sandwiches the Aira caldera (in the inner part of Kagoshima Bay)
　
On Sakurajima, magma has accumulated deep underground in the Aira Caldera (in the inner part of Kagoshima Bay) for a long period of time, and the amount of volcanic gas (sulfur dioxide) released is generally high, so effective activity is expected to continue in the future. It will be done. Please note future volcano information.

January 21, 2025, 10:13 p.m., Pacific: This is just lay opinion (no special updates from monitoring agencies), but I do think Sakurajima bears watching.

On the 19th, it did this:

Today it had this:

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And right now a steady, though relatively small ash plume is rising:

Source.

That seems like a change in behavior. Experts did a flyover after the 19th, per accounts on X that I follow, but I haven’t come across any more information yet.

Let’s wait and see what happens.

Featured image: Giovanni Zacchini/Shutterstock

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