Stop Calling It a Tidal Wave: An Editor's Honest Guide to Geology

I wince every time I hear someone call a tsunami a "tidal wave." It's not just imprecise—it's wrong. Tides have almost nothing to do with tsunamis, which are caused by undersea earthquakes or volcanic eruptions (NOAA NOS / Tsunamis). If you take one thing from this article, make it this: learn the rock cycle before you worry about the Big One. The rock cycle is the foundation of geology, and understanding it will change how you see every mountain, beach, and cliff.

What exactly is geology, anyway?

Geology is the study of the solid Earth—rocks, minerals, mountains, and landforms. It's one of the four main branches of Earth science, alongside oceanography, meteorology, and astronomy (Britannica (Earth sciences)). Within geology, you'll find specialists like mineralogists, volcanologists, seismologists, paleontologists, and geochronologists. I think the most underrated of these is geochronology—the science of dating rocks—because it gives us the deep-time perspective that makes everything else make sense. Take zircon crystals in Western Australia: they've been dated to 4.4 billion years old, meaning they formed just 160 million years after Earth itself. That's the kind of perspective geochronology offers.

Are tsunamis really tidal waves?

No. Absolutely not. Tsunamis are giant waves caused by earthquakes or volcanic eruptions under the sea. In the deep ocean, they don't dramatically increase in height—they build as they approach the coast. Their speed depends on ocean depth, not distance from the source, and they can travel as fast as jet planes over deep water (NOAA NOS / Tsunamis). Oceanographers actively discourage the term "tidal wave" because tides have little to do with them. So next time you hear it, correct it. Politely.

How often do earthquakes happen?

About 50,000 earthquakes large enough to be noticed without instruments occur every year. Of those, roughly 100 are big enough to cause substantial damage if they hit near populated areas (Britannica / Earthquake). That's not a rare event—it's a daily reality somewhere. And here's a staggering fact: about 80 percent of the energy released in earthquakes comes from quakes in the Circum-Pacific Belt, and another 15 percent from the Alpide Belt (Britannica / Earthquake). So if you live in those belts, you're in the hot zone. If you don't, you're lucky—but not immune.

Can we predict earthquakes?

No, and anyone who tells you otherwise is selling something. We can forecast probabilities, but we can't predict the exact time and place. That's why building codes and preparedness matter more than prediction. The moment magnitude scale, which replaced the older Richter scale, gives us a better measure of total energy release (Britannica / Earthquake). But it doesn't tell us when the next one hits. So stop waiting for a prediction and start bolting your bookshelves.

What's the difference between weather and climate?

This one drives me crazy. Weather is short-term—it changes minute to minute, season to season. Climate is the average of weather over time and space. As NOAA puts it, "climate is what you expect, weather is what you get" (NOAA NOS / Weather vs climate). So yes, a cold snap doesn't disprove global warming. In fact, NASA reports that Earth's global surface temperature in 2025 was 2.14 °F (1.19 °C) above the 1951–1980 average, and 2024 remains the hottest year on record since 1880 (NASA / Global Temperature). That's climate, not weather.

Why should I care about the rock cycle?

Because it explains the ground beneath your feet. The rock cycle describes how igneous, metamorphic, and sedimentary rocks transform into one another through temperature, pressure, time, and environmental changes. Igneous rocks form from magma deep underground (about 50 to 200 km down) or from lava on the surface. Sedimentary rocks form from fragments of older rocks or precipitated minerals, usually in layers, and they're where you find fossils. Metamorphic rocks form when existing rocks are cooked and squeezed, often developing banding. Understanding this cycle is like learning the grammar of the planet—it lets you read the landscape. For instance, the Appalachian Mountains were once taller than the Himalayas. Erosion over hundreds of millions of years has worn them down to their current size, and the sediment eroded from them now forms sedimentary rocks along the eastern coast of the United States.

What's the biggest misconception about volcanoes?

That they're all the same. They're not. Shield volcanoes like Mauna Loa are huge, gently sloping domes built from fluid lava eruptions. Stratovolcanoes like Mount Fuji are steep, layered cones of ash and lava. They form in different settings: stratovolcanoes at subduction zones, shield volcanoes at rift zones, and hot-spot volcanoes like those in Hawaii form from mantle plumes far from plate margins (Britannica / Volcano). And pyroclastic flows—those fluidized mixtures of hot gas and incandescent particles—are the real killers. They sweep down flanks incinerating everything in their path (Britannica / Volcano). So if you're near a volcano, know which type you're dealing with.

Bottom line

Stop calling tsunamis tidal waves, and start learning the rock cycle. It's the single best move you can make to understand geology. The rock cycle connects everything—from the mountains you hike to the fossils you find. And it's more useful than memorizing earthquake magnitudes or hurricane categories. So pick up a rock, ask where it came from, and follow the story. That's geology.

Sources

• Britannica (Earth sciences) - https://www.britannica.com/science/Earth-sciences
• Britannica / Earthquake - https://www.britannica.com/science/earthquake-geology
• NOAA NOS / Tsunamis - https://oceanservice.noaa.gov/facts/tsunami.html
• NOAA NOS / Weather vs climate - https://oceanservice.noaa.gov/facts/weather_climate.html
• NASA / Global Temperature - https://climate.nasa.gov/vital-signs/global-temperature/
• Britannica / Volcano - https://www.britannica.com/science/volcano