Panama Quake Tracker

Reading this tracker

• Color and size = magnitude. Yellow is under M4, then orange, red-orange, red, and magenta for M7 and up. Bigger dots are stronger quakes.
• Filled dots come from the Instituto de Geociencias (IGC-UP). Rings come from the USGS. The largest quake in the current filter carries a label.
• Faded dots are older than 3 hours. Untick the box above the map to show everything at full strength.
• A blue halo marks a quake that arrived in the last 20 minutes.
• Map layers (top right of the map): satellite imagery, dark or light street maps, place names, and tectonic plate boundaries. Orange lines are subduction zones, where one plate dives under another; dashed yellow lines are the other plate boundaries.
• One set of filters drives everything. Catalog, time, magnitude and search apply to the counts, map, chart, list and comparison together. Dragging across the chart sets a custom time span.
• All times are Panama local time (UTC−5).

Magnitude

Magnitude measures the size of an earthquake at its source. The scale is logarithmic: each whole step means about 10 times more ground motion on a seismograph and about 32 times more energy.

So an M7.7 releases about 5.6 times the energy of an M7.2, which is why the two agencies' figures for the October 9 quake are not a small disagreement.

Why the IGC-UP and the USGS give different numbers

• ML (local magnitude, the original "Richter" idea) is measured from nearby stations. It works well for small and moderate quakes.
• mb (body-wave magnitude) uses the first waves to arrive at distant stations. It tends to underestimate large quakes, roughly above M6.
• Mw (moment magnitude, shown by the USGS as Mww) comes from the fault area, how far it slipped and the stiffness of the rock. It does not saturate, so it is preferred for large quakes.

Magnitude is not shaking

Intensity describes how strongly the ground shook at a particular place, on the Modified Mercalli scale (I to XII). One earthquake has one magnitude but many intensities: shaking is stronger closer to the epicenter, for shallow quakes, and on soft or filled ground.

Aftershocks

• They die down over time (Omori's law). The rate drops roughly in proportion to the time since the largest quake, so day 10 has about a tenth as many as day 1. After an M7, noticeable aftershocks can continue for weeks to months.
• Small ones vastly outnumber big ones (Gutenberg–Richter law). For each step down in magnitude there are about ten times as many quakes.
• The largest aftershock is usually about 1.2 magnitude units smaller than the mainshock (Båth's law). That is an average; sequences vary.
• Sometimes a bigger one follows. In roughly 1 in 20 sequences, a later quake turns out larger. The first one is only called the "mainshock" after the fact.
• Doublets are two quakes of similar size close together in time and place.

Strong aftershocks are dangerous because buildings already weakened by the mainshock can fail. Stay out of damaged structures.

Why Panama shakes

The isthmus sits on a small block of crust, the Panama plate (often called a microplate), wedged between the Caribbean plate to the north, the Cocos and Nazca plates in the Pacific, and the North Andes block to the east. Turn on Plate boundaries on the map to see them.

• South of Azuero and Coiba, the Nazca plate grinds past the Panama plate, mostly sideways (strike-slip) with some compression. This is the zone of the October 2026 sequence.
• The Panama Fracture Zone, a north–south set of faults west of Coiba near 82–83°W, separates the Cocos and Nazca plates and produces frequent quakes off Chiriquí.
• Toward Costa Rica, the Cocos plate dives under Central America (a subduction zone, orange on the map). Much of the background activity near Puerto Armuelles, Boquete and Changuinola comes from here.
• On the Caribbean side, the North Panama Deformed Belt absorbs compression from the Caribbean plate.
• Toward Colombia and Darién, the Panama plate meets the North Andes block, and the Nazca plate dives under South America.

Large quakes have struck before. In 1882, a great earthquake off the Caribbean coast (around M7.9) caused a tsunami along the San Blas coast. In 1991, the M7.6 Limón earthquake in Costa Rica caused heavy damage in Bocas del Toro.

How fast the shaking travels

Seismic waves cross Panama's crust at a few kilometres per second. The first jolt (P wave) travels at about 6 km/s; the stronger shaking (S wave) at about 3.6 km/s; the slow rolling waves at about 3 km/s.

Rule of thumb: count the seconds between the first jolt and the strong shaking and multiply by about 8.6 km to estimate your distance from the epicenter.

Tsunami warning signs

• strong shaking, or shaking that lasts a long time, while you are near the coast
• the sea suddenly pulling back and exposing the seafloor, or rising fast
• a loud roar coming from the ocean

If you notice any of these, move inland or to high ground right away, on foot if you can. Do not wait for an official alert and do not go to the shore to watch. Tsunamis come in several waves over hours; the first is often not the largest.

Official sources: SINAPROC in Panama, and the Pacific Tsunami Warning Center at tsunami.gov.

What to do

During the shaking

• Drop, Cover, Hold On. Get down, take cover under a sturdy table, and hold on until the shaking stops.
• Do not run outside while the ground is shaking; most injuries come from falling objects.
• Outdoors, move away from buildings, trees, walls and power lines. Driving, pull over away from bridges and stay in the vehicle.

After the shaking

• Expect aftershocks. Check for injuries; in Panama call 911 for emergencies.
• If you smell gas, open windows, leave, and don't use flames or switches. Don't go back into damaged buildings.
• Send text messages instead of calling, and follow SINAPROC for instructions.

Be ready

• Keep water (about 4 liters per person per day, for at least 3 days), food, a flashlight, a radio, first aid, medicines, document copies, cash and a charger.
• Secure heavy furniture to the walls and agree on a family meeting point.

Data and resources

• IGC-UP: the Instituto de Geociencias, Universidad de Panamá, publishes the quakes it locates over the last 7 days at sismosgeociencias.up.ac.pa. Preliminary entries are automatic and change often; Reviewed ones have been checked by an analyst.
• USGS: the U.S. Geological Survey's global catalog, which for this region mostly lists quakes of about M4.5 and up.
• How it updates: on the website, an always-on checker asks the IGC-UP every 30 seconds whether its list changed and reads the USGS catalog every minute; the open page refreshes every 30 seconds. The local version on your own computer checks every couple of minutes. No AI service is involved.
• Alerts: on the website, Turn on alerts sends a notification to that phone or computer when a new quake reaches the magnitude you chose, even when the page is closed, usually within a minute of the agencies publishing it. If an agency later raises a quake's magnitude past your choice, you get a second, revised alert. On iPhone and iPad (iOS 16.4 or later), add the site to your Home Screen first and turn alerts on from there. Alerts depend on the agencies' own reporting delays and are not an early warning system.
• Matching: an IGC-UP entry and a USGS entry count as the same quake when their times are less than 20 seconds apart and their epicenters less than 100 km apart.
• Map data: satellite imagery © Esri, Maxar, Earthstar Geographics; street maps © OpenStreetMap contributors © CARTO; plate boundaries from Bird (2003), PB2002.

This tracker is for following the sequence, not for emergencies. For warnings and instructions, follow SINAPROC and the official agencies.

Glossary

Aftershock

A smaller earthquake that follows a larger one in the same area.

Båth's law

On average, the largest aftershock is about 1.2 magnitude units smaller than the mainshock.

Body-wave magnitude (mb)

A magnitude from the first waves recorded at distant stations. It underestimates large earthquakes.

Depth

How far below the surface the rupture started. Shallow quakes shake the surface more strongly near the epicenter.

Doublet

Two earthquakes of similar size close together in time and place.

Epicenter

The point on the surface directly above where the earthquake started.

Fault

A fracture in the crust along which the rocks on either side have moved.

Foreshock

A smaller earthquake before a larger one in the same place, recognized only after the larger one happens.

Gutenberg–Richter law

For each step down in magnitude, there are about ten times as many earthquakes.

Hypocenter (focus)

The point underground where the rupture began.

Intensity

How strongly the ground shook at a given place (Modified Mercalli scale, I to XII). Not the same as magnitude.

Local magnitude (ML)

A magnitude from nearby stations, the modern form of Richter's original scale.

Magnitude

The size of an earthquake at its source, on a logarithmic scale.

Mainshock

The largest earthquake in a sequence.

Microplate

A small tectonic plate, such as the Panama plate under the isthmus.

Moment magnitude (Mw, Mww)

A magnitude calculated from the fault area, slip and rock stiffness; the standard for large quakes.

Omori's law

Aftershocks become less frequent roughly in proportion to the time since the mainshock.

P wave / S wave

The first, faster compressional wave and the slower, stronger shear wave of an earthquake.

Preliminary / Automatic

An event located by computer and not yet checked by an analyst. It may change or be removed.

Reviewed

An event an analyst has checked.

Strike-slip

A fault where the two sides move sideways past each other.

Subduction

When one plate slides beneath another, as the Cocos plate does under Central America.

Tsunami

A series of sea waves caused by a sudden movement of the seafloor, usually from a large, shallow undersea earthquake.

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