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2026-08-30 00:17 (UTC+9),
E OFF CHIBA,
30km Depth, M 4.8 by JMA

Is Distribution Maximum Observed Is:4

Seismic Intensity (Is) distribution is estimated from the observed data (circles) of NIED K-NET, KiK-net, JMA, and local governments that had been collected by 2026/08/30 00:27:22.

Estimated Is for Major Cities

Max. Obs. Is Histogram
of Estimated Is
1
2
3
4
5
-
5
+
6
-
6
+
7
 Municipality
Show All Data 		Nighttime Population Distance
[km]
4
Kamisu,Ibaraki 95,000 23
3
Itako,Ibaraki 29,000 35
3
Choshi,Chiba 64,000 9
3
Asahi,Chiba 66,000 24
3
Katori,Chiba 77,000 38
3
Kashima,Ibaraki 68,000 29
3
Sosa,Chiba 37,000 32
The histogram shows frequency distribution of estimated Is derived from interpolation of the observation with 250-m mesh. The daytime and nighttime correspond to 9:00-18:59 and 19:00-8:59, respectively. The distance is measured from the epicenter to the center of the municipality.

Is Exposed-Population Estimates of Each City

5- or greater
5- or greater
Not Available
5+ or greater
5+ or greater
Not Available
6- or greater
6- or greater
Not Available
6+ or greater
6+ or greater
Not Available
color scale

Population exposed to Is 5- or greater are not estimated.

Seismic Hazard Information of J-SHIS

J-SHIS is a Web service by NIED, to help prevent and prepare for earthquake disaster by providing a public portal for seismic hazard information across Japan.

Is Distribution of 2% Probability of Exceedance in 50 Years Is Distribution of Return Period of 50,000-year

Major Historical Damaging Earthquakes in This Region

Year Region M Damage
1855 Edo, Near Edo 7.0-7.1 Edo Earthquake,Over 14,000 houses collapsed or were destroyed by fire, over 4,000 dead. About 2,600 people from Samurai families died. They say total deaths were 10,000.
1894 Eastern Tokyo 7.0 Tokyo Earthquake,Many houses collapsed in Kanda, Honjo, and Fukagawa. 24 dead in Tokyo, 7 dead in Kawasaki and Yokohama in Kanagawa.
1895 Southern Ibaraki 7.2 53 collapses (43 houses and 10 depots), 6 dead.
1915 Boso Peninsula 6.0 Some landslides. 5 injured, some houses collapsed.
1921 Southern Ibaraki 7.0 Ryugasaki Earthquake,Minor damage in Chiba and Ibaraki such as damage to houses and roads.
1938 Off Ibaraki 7.0 250 houses damaged in Fukushima. 1 depot collapsed in Ibaraki. A small tsunami was observed.
1987 E Off Chiba 6.7 2 dead, 161 injured in Chiba. 16 houses collapsed and over 70,000 partially destroyed. Many roads damaged.
2011 Hamadori, Fukushima 7.0 The crustal earthquake with normal faults, induced by the 2011 off the Pacific Coast of Tohoku Earthquake. 4 dead, 10 injured (as of March 2016). Maximum Is was 6-.
2012 E Off Chiba 6.1 The crustal earthquake with normal faults, induced by the 2011 off the Pacific Coast of Tohoku Earthquake. 1 dead, 1 injured. Maximum Is was 5+.
Reference: National Astronomical Observatory of Japan, Chronological Scientific Tables, Maruzen, (2017) *partially extracted