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Japan · Chiba Prefecture

M5.5 Earthquake near Asahi, Chiba Prefecture (Japan)

UTC time: 2026-10-28 15:07:52 UTC Local time: —
Earthquake newsQuakeMap24
First published: Content updated:

Automatically generated from measurement data by QuakeMap24. Values may change after further analysis.

Map

M5.5 Earthquake near Asahi, Chiba Prefecture (Japan) · 2026-10-28 — Map showing the location of the epicenter
M5.5 Earthquake near Asahi, Chiba Prefecture (Japan) · 2026-10-28 — Map showing the location of the epicenter

About this earthquake

On October 28, 2026 at 15:07 UTC, a magnitude M5.5 earthquake occurred near Asahi, Chiba Prefecture (Japan). With a focal depth of about 41 km, this was a shallow earthquake, whose shaking is usually felt more strongly at the surface. Earthquakes of this magnitude can damage poorly built structures.

The data is provided by USGS and cross-checked across seismological networks. Japan: over the past 24 hours, QuakeMap24 logged 4 earthquakes, the strongest at M4.1.

Details

ID
c4a5a5ed0e9d8ec0746c4b5de1d3c07c1da5d81d
Magnitude
M5.5
Depth
41.4 km
UTC time
2026-10-28 15:07:52 UTC
Local time
—
Country
Japan
State
Chiba Prefecture
City
Asahi
Source
usgs
Coordinates
35.70150, 140.70590
Temperature
14.1°C

Depth profile

Depth profile Depth: 41.4 km (Shallow) Surface Shallow Intermediate Deep 0 km 70 km 300 km 700 km 41.4 km
Shallow
41.4 km
41.4 km — deeper than the regional average (33.9 km)
Regional average: 33.9 km
Why depth matters

Shallow quakes release energy near the surface — shaking is felt more strongly and damage potential is higher.

Depth classes per USGS

Felt reports

81felt reports at EMSC / LastQuake

Voluntary reports of feeling this earthquake. The count is not an intensity measurement and is not added to USGS DYFI reports.

Data updated: Oct 29, 2026, 12:26 AM UTC · Last checked: Nov 5, 2026, 6:37 PM UTC

Source: EMSC / LastQuake

Estimated impact

Green No or minimal impact expected.
Estimated population exposed
IV 22'731'120
V 116'253
57 Felt reports · max reported intensity 3.9

Ground shaking

V
Moderate · Intensity (MMI) V
Felt by all, slight damage possible.

Tectonic context

Located on the Okhotsk Plate.
Near the boundary Okhotsk ↔ Philippine Sea · about 122 km away

Nearby population centers

Distances are straight-line distances from the epicenter. Population data: GeoNames.

PlaceDistanceDirectionPopulation
Asahi5.3 kmW64'690
Narita36.3 kmW132'906
Chiba54.4 kmW979'768

GeoNames · CC BY 4.0

Volcanoes nearby

  • Takaharayama
    Distance: 157 km ·Stratovolcano ·Elevation: 1'795 m ·Last eruption: -4570 ·Japan
  • Nantaisan
    Distance: 161 km ·Stratovolcano ·Elevation: 2'486 m ·Last eruption: -9540 ·Japan
  • Hakoneyama
    Distance: 161 km ·Complex ·Elevation: 1'438 m ·Last eruption: 2015 ·Japan
  • Izu-Oshima
    Distance: 161 km ·Stratovolcano ·Elevation: 758 m ·Last eruption: 1990 ·Japan
  • Omanago Group
    Distance: 165 km ·Lava dome(s) ·Elevation: 2'341 m ·Last eruption: -3050 ·Japan
  • Akagisan
    Distance: 166 km ·Stratovolcano ·Elevation: 1'828 m ·Japan

Radius · 100 km

Nearby infrastructure

Up to 3 nearest sites per category

Airports

  • Narita International AirportJapan · NRT · RJAA
    29.6 kmStraight-line distance
  • Ibaraki AirportJapan · IBR · RJAH
    59.5 kmStraight-line distance
  • Tokyo Haneda International AirportJapan · HND · RJTT
    84.8 kmStraight-line distance

Source: OurAirports · Dataset date: 2026-11-05

Nuclear power plants

  • Tokai nuclear power plantJapanUnder construction · Permanently shut downReactor units at site: 2
    80.6 kmStraight-line distance
  • Japan Power Demonstration Reactor nuclear power plantJapanPermanently shut downReactor units at site: 1Approximate location
    84.5 kmStraight-line distance

Source: Global Energy Monitor · Global Nuclear Power Tracker · Dataset date: 2026-08

This selection shows geographic proximity, not a hazard zone or confirmed impacts. Distances use recorded site coordinates. Sources & data dates

Subsequent earthquakes nearby

Events recorded after this earthquake within 150 km. They are not automatically classified as aftershocks.

First 6 hours4
First 24 hours4
First 72 hours4
Strongest subsequent eventM5.4
M3.12026-10-28 17:45:00 UTC123.5 kmHitachiota M4.42026-10-28 18:32:00 UTC0.6 kmAsahi M3.52026-10-28 20:22:00 UTC0.6 kmAsahi M4.32026-10-28 20:22:30 UTC17.3 kmChoshi M4.72026-11-03 05:40:00 UTC9.6 kmSosa M5.42026-11-03 05:40:15 UTC65.9 kmIchihara M3.42026-11-03 20:34:00 UTC43.5 kmChosei M3.42026-11-05 02:35:00 UTC109.8 kmMinamiboso

Comparison of seismic sources

7 sources currently report magnitudes from M5.4 to M5.7.

Measurements can differ because agencies use different networks and calculation methods. Values may be revised.

SourceMagnitudeDepthPosition difference
JMAM5.450.0 km0.6 km
BMKGM5.610.0 km35.5 km
EMSCM5.616.0 km15.2 km
SERBIA_RSZM5.710.0 km43.9 km
USGSM5.541.4 km0.0 km
GAM5.448.0 km7.9 km
GFZM5.653.0 km6.1 km

Chiba Prefecture

Context for this earthquake

05 Oct 2025 – 05 Oct 2026 · M ≥ 3.0 · 34 Catalogue entries

Sufficiently reliable matching data are not currently available for a direct comparison. The area profile shows the available records and their limitations.

Open seismic profile

Historical context nearby

Comparison with recorded earthquakes before this event within 150 km.

Magnitude rank#9
Earlier events M≥4148
Earlier events M≥546
Compared since2025-01-04

The QuakeMap24 comparison dataset begins on 2024-03-23. Earlier earthquakes may not be included.

Strongest earlier events

M6.02026-08-22 17:00:40 UTC58.1 kmAbiko M5.92026-06-26 03:46:36 UTC22.0 kmChoshi M5.82026-06-26 03:46:37 UTC31.1 kmSammu M5.82026-06-26 03:46:36 UTC19.3 kmYokoshibahikari M5.62026-06-16 10:46:27 UTC92.1 kmNoda

Historic earthquake map · Japan

Open history map
Explore recent and long-term earthquake activity in this country. Use filters to narrow down by magnitude, depth, and date range.

Country statistics · Japan

Country overview
View earthquake KPIs, strongest and latest events, and averages for this country.

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