Three-component unfiltered seismogram showing 24 hours of data, recorded at IAVAL on 25th October 2010. Z, N and E indicate components of the ground motion in the vertical, North, and East directions, respectively.

Three-component seismogram with a 10-second low-pass filter applied (high frequencies corresponding to wave periods shorter than 10 seconds are removed), zoomed in on the recording of the Indonesian event at IAVAL on 25th October 2010.

Three-component seismogram with a 10-second high-pass filter applied (low frequencies corresponding to wave periods longer than 10 seconds are removed), showing 24 hours of data at the station IAVAL on 25th October 2010. The "ambient noise" that dominates the seismograms is primarily a superposition of numerous seismic waves that are excited by ocean waves as they crush into the continental shelf. The arrow indicates an increase in the wind speed during this day (as confirmed by the weather report, below), causing an increase in the energy of the ocean waves and, consequently, an increase in the amplitude of the ambient noise recorded by our seismometers.

Date

Rainfall (mm)

Max Temp (°C)

Min Temp (°C)

Grass Min Temp (°C)

Mean Wind Speed (knots)

Gusts (if >= 34 knots)

Sunshine hours

Day of the seismogram: weather changing

Day after: very windy