Which instrument records seismic ways from a earthquake?

Seismograph or seismometer

are the same so you could use either.

seismograph

The instrument that records seismic waves from an earthquake is called a seismograph. Seismographs are designed to detect and measure the ground motion caused by seismic waves. The recorded output of a seismograph is called a seismogram, which provides valuable information about the earthquake, such as its magnitude, duration, and the types of waves it generated.

To analyze and study seismic waves using a seismograph, follow these steps:

1. Setup: Install a seismograph in a stable location, typically on the surface or in a borehole, where it can directly measure ground motion. The seismograph includes a mass suspended on a spring or pendulum system, along with a recording device.

2. Calibration: Before recording actual seismic waves, it's important to calibrate the seismograph. This involves applying a known input (such as an artificial shaking) and observing the output recorded on the seismogram. Calibration ensures that the instrument is accurate and sensitive to seismic events.

3. Recording: Once the seismograph is calibrated, it can be left to continuously record ground motion. When an earthquake occurs, the seismograph's mass will remain stationary due to inertia while the ground moves beneath it. This displacement is converted into an electrical signal that is recorded on the seismogram.

4. Interpretation: After the seismic waves are recorded, the seismogram can be analyzed to determine various characteristics of the earthquake. The seismogram displays the ground motion over time, with distinct wave signatures indicating different types of seismic waves (e.g., P-waves, S-waves, surface waves). Analyzing the amplitude, frequency, and duration of these waves helps seismologists understand the earthquake's magnitude, depth, and epicenter.

By using seismographs, scientists can gather crucial data about earthquakes and contribute to our understanding of seismic activity, which has significant implications for geology, engineering, and public safety.