In just five days, a series of earthquakes de magnitude 4.2 scattered across Asia and America. All of them are classified as moderate earthquakes and, although they have been felt unevenly, records indicate intensities ranging from weak to moderate near the epicenters.
The episodes were located in Philippines (Visayas and Samar), the andaman sea (India), Ecuador (Saraguro area), the central coast of Peru and the western TibetNext, we review the times, depths, reported intensities, and nearest cities in each case of these recent earthquakes.
Chronology of earthquakes mag. 4.2
Nov 14, 07:16 UTC – Eastern Samar (Philippines): event at a depth of 10 km with MMI IV (light tremor) according to EMSC, initially reported by PHIVOLCSCatbalogan is about 75 km SW of the epicenter and few citizen reports were received.
Nov 16, 16:21:25 UTC – Andaman Sea (India)The TMD confirmed a magnitude of 4.2 and 10 km in depth, with MMI IV near the epicenter. Port Blair (Andaman and Nicobar) is located 275 km to the west; the nearest volcano is Barren Island, about 147 km.
Nov 17, 03:47:40 UTC – Saraguro Zone (Ecuador): very shallow earthquake, 5 km, with perceived intensities between MMI IV and MMI VModerate shaking was reported in nearby areas (e.g., reports of MMI V in Piñas/Zaruma and MMI IV in Oña). Cuenca is at 91 km NE of the epicenter.
Nov 17, 04:58:01 UTC – Central coast of Peru (23:58 local time on Nov 16): depth 37 kmestimated intensity MMI III near the epicenter, with few citizen reports. Barranca is located approximately 73 km E of the earthquake zone.
Nov 18, 04:15:45 UTC – Ngari (Tibet, China): The USGS confirmed magnitude 4.2 and 10 km at a depth of 4, with MMI IV in the epicenter. This is a remote area of western Tibet, with no citizen reports at the time of the update.
Nov 18, 11:36:48 UTC – Visayas Sea (Philippines): shallow earthquake, 5 kmfelt moderately in surrounding areas (EMSC/PHIVOLCS). MMI II-III reports were received in the Cebu area and one MMI IV report in starCebu City is located at 89 km south of the epicenter.
Reported impact and intensities
The reported intensities ranged between MMI III (weak tremor) y MMI V (moderate tremor), with no reports of severe shaking. In Ecuador, some residents described brief but strong shaking very close to the epicenter, while in Philippines There were warnings of weak to moderate tremors in municipalities of the Visayas.
In other cases, such as the andaman sea and the TibetNo citizen reports were registered in the first few hours, even though intensity models placed the tremor at light levels near the epicenter. On the coast of Peru The event was deeper (37 km), which usually dampens the movement on the surface.
Agencies and data quality
The parameters of the earthquakes come from official sources , the EMSC (Euro-Mediterranean Seismological Centre), USGS (U.S. Geological Survey), PHIVOLCS (Philippines) and the TMD from Thailand (for Andaman). In some cases the initial state was automatic and, after a few minutes, the values of magnitude and depth They were refined manually.
The lists consulted indicate that no aftershocks had been detected in the hours following several of these events. Furthermore, the consistency of parameters between different agencies increases confidence in the final solutions, especially in magnitude 4.2 and depths of 5 to 10 km (with the exception of Peru, 37 km).
What does a 4.2 mean and how is it perceived?
An earthquake of magnitude 4.2 It releases approximately 1,3 × 10^11 joules (approximately 35 MWh), equivalent to about 30 tons of TNT. In terms of perception, in nearby areas it can feel like a slight or moderate tremor (MMI III–V), capable of moving small objects, but without causing structural damage to well-built buildings.
La intensity felt It depends on multiple factors: distance to the epicenter, depth, soil type, duration of the shaking, and local conditions. Therefore, shallow earthquakes of 5–10 km can be felt more in the immediate vicinity than one of the same magnitude at a greater depth. tens of kilometers deep.
Conditions at the epicenters and surrounding areas
The observations included environmental data: in the andaman sea Clear skies and 28°C were reported; in the earthquake of Peru, broken clouds and 18 °C; in the TibetOvercast skies and sub-zero temperatures; in the Visayas, clouds and around 28°C. This data does not determine seismicity, but illustrates the context that residents faced when They noticed the tremor..
The sequence of events confirms that, even on quiet days, global seismic activity maintains regular pulses of magnitude 4.2 on different plate margins. With information consolidated by EMSC, USGS, PHIVOLCS and TMD, the outlook points to episodes of mild to moderate shaking, few citizen reports and no significant aftershocks in the first few hours.
