As we all know, all data science projects include three parts: retrieving data, numerical computation and result visualization. Take seismology as an example, ways for requesting seismic data from providers (IRIS, ISC and NIED etc.) are concluded here.

Thus, this post focuses on collecting serveral useful python library for general scientific numerial computation and visualization.

## Mathmatical expression

For scientific purpose, we sometime need to shift phase of time series with specfic angles. To acheive this, we can transform the time series into freqeuency domain with $$F(\omega) = \int_{-\omega}^{\omega} f(t) e^{-i \omega t} dt$$

where $F(\omega)$ as Fourier spectrum of signal $f(t)$. Thus, the phase shifted Fourier spectrum $F_{sh}$ is

$$F_{sh}(\omega) = F(\omega) * e^{-i \alpha}$$

Collection of all known data providers and comparison between them.

Including earthquake location, waveforms, mechanism and earth reference models.