SeismoScope PH

Data source: SQL Server

Last hour activity

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Magnitude trend (map window)

Seismic activity · past 24 hours

27 Dec 2025 18:06 – 28 Dec 2025 18:06 (Asia/Manila)

Magnitude trend (3D window)

Depth distribution (3D)

27 Dec 2025 18:06 – 28 Dec 2025 18:06 (Asia/Manila)

Weekly Seismic Overview

Seismic Activity Report: Philippines (Last 7 Days)

Overview:

In the past week, the Philippines experienced a total of 280 seismic events, with a notable range of magnitudes and depths. This report highlights the significant trends, clusters, and notable events, particularly focusing on the magnitude ranges and trench involvement.

Magnitude Distribution:

The seismic events ranged from minor tremors (magnitude 1.4) to significant quakes (magnitude 6.6). The majority of the recorded events were of low magnitude, with 1.4 to 2.9 being the most common range, accounting for approximately 70% of the total occurrences. Notably, the strongest event recorded was a magnitude 6.6 earthquake on December 27, 2025, located 429 km north of Itbayat in Batanes, which occurred at a depth of 68 km. This event is significant not only due to its magnitude but also because of its potential impact on the northern regions of Luzon.

Clusters and Regions of Interest:

The seismic activity was distributed across various regions, with Luzon, Visayas, and Mindanao being the most affected areas. Luzon reported a higher frequency of events, particularly in the Zambales and Ilocos regions, where multiple tremors were recorded, including a notable magnitude 4.8 quake on December 28, 2025, near Palauig, Zambales.

In the Visayas, the region of Cebu and surrounding areas experienced several low to moderate magnitude events, with a peak magnitude of 4.0 recorded near Gamay, Northern Samar. Mindanao also showed significant activity, particularly in the Davao region, where multiple events of magnitudes ranging from 2.0 to 4.0 were reported.

Depth Analysis:

The depths of the seismic events varied widely, with many shallow earthquakes recorded at depths less than 10 km, particularly in the Visayas region. However, deeper events were also prevalent, with some reaching depths of over 100 km. The depth of the significant 6.6 magnitude earthquake was 68 km, indicating a deeper tectonic interaction, possibly related to the subduction zones in the region.

Trench Involvement:

The seismic activity in the Philippines is closely linked to the complex tectonic setting involving the Philippine Trench and the Manila Trench. The occurrence of the 6.6 magnitude earthquake suggests significant tectonic stress in the region, likely related to the subduction processes occurring along these trenches. The clustering of seismic events near these trenches indicates ongoing tectonic activity, which is a characteristic feature of the region.

Conclusion:

The last seven days have shown a mix of minor and significant seismic activity across the Philippines, with a notable cluster of events in Luzon and Mindanao. The presence of a major earthquake at a considerable depth suggests ongoing tectonic processes, with implications for future seismic hazards. Continuous monitoring and analysis of these events are essential for understanding the seismic risks in this seismically active region.

AI-generated report created on 2025-12-28T08:00:12.695439+08:00 (gpt-4o-mini).

Magnitude & Slip Summary

Latest AnalysisMath snapshot · 2025-12-28T00:30:00.967401+00:00 UTC · Window 30 days

Events analysed
1321
Mean magnitude
2.36
Strongest magnitude
6.60
Events M ≥ 4.0
46
Events M ≥ 5.0
5
Gutenberg–Richter b-value
0.74
Total seismic moment
10.01 ×10¹⁸ Nm
Radiated energy
563036.31 GJ
Equivalent slip
3.97 cm
Slip rate (approx.)
1.36 mm/day
Moment rate
0.34 ×10¹⁸ Nm/day
Energy proxy
500617.94 GJ
Data coverage
29.2 days

Slip estimates assume a 120 × 70 km fault and shear modulus of 30 GPa.

Daily earthquakes (30 days)

Daily seismic moment release

7-day Seismic Heat Map

Trench Contribution

The pie chart highlights which trenches account for the bulk of recent seismic activity.

Depth Distribution Histogram

Depth bins highlight how seismicity concentrates from shallow crustal levels to deep subduction zones.

Philippines 3D Cross-Section

The analysis of fracture clusters beneath the Philippines reveals critical insights into the region's tectonic dynamics and associated seismic hazards. Our examination here, based on event clusters, centroids, and depth ranges, identifies key characteristics of nine clusters across the area, each with distinct implications for seismic activity and hazard evaluation.

Cluster Overview:

Centroid located at 157.7 km along-strike and -40.6 km across-strike. This cluster is the most active, indicating a significant concentration of seismicity. Geographically, it aligns closely with the Manila Trench, suggesting it may be influenced by subduction processes.

Positioned at approximately 392.7 km along-strike, this cluster is situated in the eastern region near the Philippine Trench. The deeper average depth (26.3 km) suggests a relationship with the trench's activity and potential for larger subduction zone earthquakes.

Cluster 3, at -171.4 km along-strike (near the Mindanao region), shows a range of depths (2.0–101.0 km) indicating more complex tectonic interactions. In contrast, Cluster 4, located at -193.9 km, has a similar depth range (1.0–59.0 km) but lacks significant seismicity, perhaps indicating a less active tectonic environment.

These are less active, with clusters occurring at spatially more distant positions from major trenches. Clusters 5 (-107.2 km) and 6 (-191.9 km) have depths of about 6.0–30.0 km and 7.0–37.0 km, respectively, yet they may represent evolving stress fields rather than stable fault lines.

Clusters 7 (273.1 km) and 9 (-279.5 km) demonstrate mild seismicity, with narrower depth ranges, possibly indicating minor tectonic adjustments. For instance, Cluster 9’s location in a complex region suggests intricate interactions between nearby geological formations. Cluster 8 is very localized and characterized by shallow depths (1.0–33.0 km), indicating potentially minor, shallow crustal faults.

With shallow depths, Cluster 11 (266.4 km) shows less seismic activity and could suggest a stable area or insufficient data coverage.

Tectonic Implications:

The presence of these clusters indicates that the Philippines is situated at a critical convergent boundary with the Eurasian Plate and the Philippine Sea Plate. The more active clusters (1 and 2) align with significant geological features that drive earthquake generation, while the less active clusters can indicate areas of stress accumulation or tectonic quiescence.

Hazard Implications:

The primary risk from the identified clusters, particularly from Clusters 1 and 2, is the likelihood of significant seismic events affecting densely populated regions. As such, a better understanding of these clusters can aid in informing earthquake preparedness and risk mitigation strategies.

In conclusion, the analysis provided here illustrates not only the seismicity of the Philippines but the importance of monitoring these clusters to improve hazard assessments and readiness. This understanding can facilitate better urban planning and disaster response strategies in an earthquake-prone region.

This analysis was generated by the AI model GPT-4.

  • Cluster 1 (3012 events, depth range 1.0–51.0 km):
  • Cluster 2 (2040 events, depth range 1.0–79.0 km):
  • Clusters 3 and 4 (196 and 95 events, respectively):
  • Clusters 5 and 6 (27 and 18 events):
  • Clusters 7, 8, and 9 (58, 15, and 70 events):
  • Cluster 11 (25 events):

Seismic Activity Forecast (24 hours)

Mappa di previsione sismica nelle Filippine
Ultimo aggiornamento blob: 2025-12-28T00:00:05+00:00 · 450.0 KB

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EarthquakesPH · 8234 records

2025-10-01T08:01:00+08:00 – 2025-12-29T01:52:00+08:00

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Data source: DOST-PHIVOLCS (Department of Science and Technology – Philippine Institute of Volcanology and Seismology).