RiskEvents
MonitoringMedium impactAI Generated

M5+ Earthquake Strikes Gunma and Saitama, Japan – No Tsunami

Occurred 16 Jun 2026·Detected 19 Jun 2026·
🇯🇵 Southern Gunma and northern Saitama prefectures, Kanto region, Honshu, Japan; felt across the Greater Tokyo metropolitan area6 reports
Natural CatastrophePropertyMarine CargoEnergy

A significant earthquake was recorded on 16 June 2026 at 19:46 JST, with seismic intensity 5-weak (JMA scale) observed in southern Gunma and northern Saitama prefectures, Japan. Intensities of 4 and 3 were felt across a wide area including Tokyo's 23 wards, Ibaraki, Tochigi, Chiba, and Kanagawa. No tsunami threat was issued. The event warrants monitoring for insured property losses in the Greater Tokyo metropolitan corridor, though magnitude and damage details are still emerging.

AI-generated from linked source reports. See our correction policy.

Impact verdict

Medium impact. Loss pathway: The earthquake produced JMA intensity 5-weak in two prefectures and was felt across the densely insured Greater Tokyo metropolitan area, including all 23 Tokyo wards, creating plausible exposure to residential and commercial property portfolios and business interruption. Evidence: Intensity 5-weak in Gunma South and Saitama North; intensity 3-4 across Tokyo, Kanagawa, Chiba, Ibaraki, and Tochigi. Limit: Magnitude (Mw) is not yet reported, no damage or insured loss estimate is available, and the JMA 5-weak intensity is moderate on the scale (maximum 7), suggesting damage is likely localised rather than catastrophic. WATCH for magnitude and damage assessment to determine if escalation to HIGH is warranted.

View assessment methodology

How we grade what we know -- Known · Reported · Uncertain. Methodology →

Intelligence ledger

Each line expands in place to its underlying sourced claim.

Known5 lines

Earthquake occurred 16 June 2026 at 19:46 JST▾
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JMA intensity 5-weak observed in southern Gunma and northern Saitama▾
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JMA intensity 4 observed in Ibaraki (north and south), southern Tochigi, southern Saitama, and Chichibu region▾
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JMA intensity 3 observed in northern Tochigi, northern Gunma, northwestern Chiba, Tokyo 23 wards, eastern Tama, and Kanagawa (east and west)▾
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No tsunami threat issued▾
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Reported1 line

Event is described as an earthquake速報 (earthquake速報/quick report)▾
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No separate sourced-claim record is available for this line yet.

Uncertain4 lines

Earthquake magnitude (Mw) not stated in this速報▾
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No separate sourced-claim record is available for this line yet.
Depth and epicentre details not provided in this report▾
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No separate sourced-claim record is available for this line yet.
No damage or casualty information available▾
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No separate sourced-claim record is available for this line yet.
No insured loss estimate available▾
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No separate sourced-claim record is available for this line yet.

Geographic Zone Matches

1 active match

  • Pacific Ring of Fire
    Rule-basedConfidence 100%

Geographic zone matches are RiskEvents spatial/analytical indicators, not coverage determinations or Lloyd's official classifications.

Affected countries

🇯🇵 Japan

Timeline

Status Change19 Jun 2026, 09:31

Status changed to monitoring

Auto-transitioned: no updates for 6 hours

active -> monitoring

Status Change19 Jun 2026, 02:19

Status changed to active

evidence_trigger: developing_promotion

developing -> active

Corroboration19 Jun 2026, 02:19

An earthquake caused JR East to suspend Joetsu Shinkansen services between Omiya and Niigata stations and Hokuriku Shinkansen services between Omiya and Nagano stations for safety checks. Service resumption is expected around 9:45 PM. The event affects critical Japanese high-speed rail infrastructure but no insured loss estimates are provided.

Source: NHK News (Japanese) (Mainstream Media) · View source

Status Change19 Jun 2026, 02:18

Status changed to developing

evidence_trigger: corroboration >= 2

signal -> developing

Corroboration19 Jun 2026, 02:18

An earthquake registering seismic intensity 5-lower (JMA scale) was observed in southern Gunma Prefecture and northern Saitama Prefecture on the evening of 16 June 2026. No tsunami warning was issued. The event occurred near the greater Tokyo metropolitan area; commercial and industrial insurance implications remain unclear pending damage reports.

Source: NHK News (Japanese) (Mainstream Media) · View source

Initial Detection19 Jun 2026, 02:16

Initial Detection

A significant earthquake was recorded on 16 June 2026 at 19:46 JST, with seismic intensity 5-weak (JMA scale) observed in southern Gunma and northern Saitama prefectures, Japan. Intensities of 4 and 3 were felt across a wide area including Tokyo's 23 wards, Ibaraki, Tochigi, Chiba, and Kanagawa. No tsunami threat was issued. The event warrants monitoring for insured property losses in the Greater Tokyo metropolitan corridor, though magnitude and damage details are still emerging.

１６日午後７時４６分ごろ地震がありました。▼震度５弱が、群馬県南部、埼玉県北部。津波の心配なし。

Source: NHK News (Japanese) (Mainstream Media) · View source

Lloyd's classifications

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