Những trận động đất người dân cảm nhận năm 2026

How to read it

Each star is the epicentre of one earthquake, sized by its magnitude and labelled with the place USGS names and the date (UTC). Around it, two kinds of evidence share one colour scale, the Modified Mercalli intensity, from I (not felt) to IX (violent):

The lines are modelled. They are USGS ShakeMap contours: USGS’s estimate of how strongly the ground shook, at every half step of intensity, computed from the earthquake and constrained by recordings and reports where there are any.

The dots are reported. Each dot is a 10 km square where people answered USGS’s “Did You Feel It?” questionnaire, coloured by the intensity their answers add up to. A faint dot rests on a single answer.

Which earthquakes, and why

The five strongest earthquakes of 2026 (1 January to 28 September) whose epicentre lies within 60° of Tucson, Arizona, and which at least 100 people reported feeling: M7.5 Venezuela, M7.4 Colombia, M7.3 Mexico (Chiapas coast), M6.5 Mexico (Guerrero) and M6.1 off western Cuba. The 60° limit comes from an earlier idea for this map, centred on the seismic station in Tucson; it is why the five all lie in the Americas.

Two strong earthquakes are not shown. An M7.2 struck near San Felipe, Venezuela, 33 seconds before the M7.5 and about 150 km away; no recording or report can tell the two apart, and the M7.5’s ShakeMap and reports cover both. An M6.7 in southern Peru was reported by 75 people, under our threshold of 100.

What the five show

Magnitude is not what people feel. The M6.1 off Cuba drew 5,777 reports, more than the other four together, because it was felt in Florida: 4,851 of the 5,083 answers that could be placed come from there, 230 from Cuba. Its strongest report is 5.6, “moderate”. The M7.4 in Colombia was 108 km deep, so its shaking was spread wide rather than concentrated: strong (VI and above) in 50 squares. The shallow M7.5 in Venezuela, 10 km deep, shook a tight area severely: its ShakeMap reaches 8.5, between severe and violent.

What we did to the data

Nothing to any value. Magnitudes, depths, places, times, ShakeMap contours and their colours, and every reported intensity, response count and distance are USGS’s, as downloaded on 28 September 2026. The ShakeMap versions are recorded with the data.

The squares became dots. USGS publishes each report square as its four corners; we place one dot at their average, the square’s centre. At this scale a 10 km square is a few pixels wide, and a dot is what can be seen.

The report colours are USGS’s classes. A square’s intensity is a decimal (for example 4.3); it takes the colour of the class it falls in, rounded to the nearest whole intensity, with II and III sharing a class. The classes, their names and their colours are those of the legend USGS publishes with every ShakeMap (after Worden et al. 2012); we took each colour from that legend at the centre of its class. None of the squares reaches X, so the scale stops at IX.

Single answers are drawn fainter, not removed. 505 of the 1,140 squares rest on one answer. Some of them, far from the epicentre, report shaking nobody near them did, and USGS’s own maps show them all the same; so do we, at a third of the strength.

Our choices: which five earthquakes (above), the projection and the frame, the dot size, the star sizes by magnitude, and the label text, which is USGS’s place description followed by the date.

Where it misleads

Reports follow people, not shaking. Where nobody lives, or nobody answers, there are no dots however hard the ground shook; the open sea has none. Many dots mean many people, not strong shaking.

Not every report is on the map. USGS counts 8,813 answers for the five earthquakes; 8,056 of them could be placed in a 10 km square. The rest have no location precise enough.

Reports far away are uncertain. The Colombian earthquake was reported felt nearly 3,000 km away, by two or more people in the same square, and one person at a similar distance reported strong shaking. Where two or more answers agree, strong shaking (VI and above) reaches 254 km from the epicentre. People in tall buildings can feel a large, deep earthquake very far off; people can also mistake another cause for one. We cannot tell which, and neither does the data.

The contours are a model. Offshore and in thinly instrumented places, ShakeMap relies on its model more than on measurements.

Why this projection

Lambert azimuthal equal-area, centred on the five epicentres (81.9° W, 13.0° N): areas keep their true proportions, so the area one earthquake shook can be compared fairly with another’s. Shapes stretch slightly towards the edges of the frame.

What it is made of

Earthquakes, ShakeMap contours and Did You Feel It? reports: U.S. Geological Survey, ANSS Comprehensive Catalog (ComCat) and its event products, downloaded 28 September 2026 (doi:10.5066/F7MS3QZH). USGS data are in the U.S. public domain. Land and ocean: Natural Earth, public domain.