Earthquake in Bangladesh (1921-2025)
I recently prepared a comprehensive map visualizing earthquake events recorded in Bangladesh between 1921 and 2025. The dataset was collected from the USGS Earthquake Catalogue (CSV format) and processed into a spatial layout using ArcMap 10.8.
📌 Data Collection & Processing
Earthquake records (magnitude, location, depth, year) were downloaded from the USGS catalogue in CSV format. Data was cleaned and structured in Excel for GIS use. The CSV file was geocoded in ArcMap using latitude and longitude, enabling precise visualization. Magnitudes were categorized into six classes (3.5–6.9) to reflect seismic intensity.
📈 Key Interpretation
- Total Events Mapped: 128 earthquake events from 1921–2025.
Northeast Bangladesh (Sylhet-Mymensingh-Sunamganj-Habiganj)
Highest earthquake concentration; magnitudes mostly 4.0-5.5, some >5.7. Dense clustering near Dauki Fault, Sylhet trough, and Indo–Burma Subduction Front indicates ongoing tectonic deformation. Depths 10–56 km show complex crustal interactions.
Chattogram-Cox’s Bazar-Hill Tracts
Second most active corridor; frequent 4.0-5.5 magnitude events. Depths 10–50 km (shallow & intermediate) typical of Indo-Burma Arc. Clusters around Bandarban-Rangamati indicate continued compressional stress.
Central Bangladesh (Dhaka-Narsingdi-Gazipur)
Fewer events, magnitudes 4.0-5.4. Recurring shallow quakes around Dhaka highlight latent seismic vulnerability.
Northwest Zone (Rajshahi-Rangpur-Kurigram)
Moderate but persistent seismicity; magnitudes 3.7-4.8, occasional up to 5.2. Reflects low-to-moderate crustal stress.
Barishal & Southern Coastal Belt
Lowest earthquake frequency. Past moderate-to-strong quakes (6.4 in 1921, 5.8 in 1989) indicate rare but powerful events. Low event count does not mean low risk due to soft deltaic sediments.
Temporal Pattern (1921-2025)
Event records rise after 1995 due to better detection and moderate quake frequency. Multiple events in 2003, 2007, 2008, 2011 suggest localized bursts. Recent 2023-2025 quakes continue in central and northeast zones.
Magnitude Profile
Most events 3.7-5.5 magnitude. Strong quakes >5.5-6.9 in 1921, 1923, 1935, 1945, 1959, 1963, 1969, 1970, 1978, 1988, 1989 mark historical high-energy periods. Depths mainly 10-40 km, typical of shallow crustal seismicity in Bangladesh.
Overall Seismic Hotspots Identified
- Sylhet-Mymensingh Corridor
- Chattogram-Cox’s Bazar-Hill Tracts Arc
- Dhaka and surrounding central districts (moderate but significant)
- Isolated strong events in the coastal south and northwestern districts
📊 Summary Tables
1. Number of Events per Year
| Year | No. of Events |
|---|---|
| 1921 | 1 |
| 1923 | 1 |
| 1931 | 1 |
| 1935 | 1 |
| 1945 | 1 |
| 1956 | 1 |
| 1959 | 1 |
| 1963 | 2 |
| 1968 | 2 |
| 1969 | 1 |
| 1970 | 2 |
| 1978 | 1 |
| 1979 | 2 |
| 1982 | 4 |
| 1986 | 2 |
| 1988 | 3 |
| 1989 | 2 |
| 1990 | 1 |
| 1991 | 4 |
| 1992 | 3 |
| 1995 | 2 |
| 1996 | 4 |
| 1997 | 2 |
| 1998 | 1 |
| 1999 | 1 |
| 2000 | 1 |
| 2001 | 5 |
| 2002 | 4 |
| 2003 | 7 |
| 2004 | 1 |
| 2005 | 4 |
| 2006 | 2 |
| 2007 | 5 |
| 2008 | 12 |
| 2010 | 1 |
| 2011 | 4 |
| 2012 | 2 |
| 2013 | 2 |
| 2014 | 3 |
| 2015 | 4 |
| 2016 | 2 |
| 2017 | 3 |
| 2018 | 1 |
| 2019 | 1 |
| 2020 | 5 |
| 2022 | 2 |
| 2023 | 5 |
| 2025 | 6 |
2. Magnitude Distribution (Classes)
| Magnitude Range | No. of Events |
|---|---|
| 3.5 - 4.1 | 30 |
| 4.2 - 4.5 | 44 |
| 4.6 - 5.0 | 28 |
| 5.1 - 5.5 | 16 |
| 5.6 - 5.9 | 8 |
| 6.0 - 6.9 | 2 |
#Bangladesh #Earthquake #DRR #EnvironmentalScience #DisasterManagement #USGS #Research #GIS #HazardMapping #Environment #ArcMap #ArcGIS #RemoteSensing
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