Václav Láska (mathematician)
Appearance
![](http://upload.wikimedia.org/wikipedia/commons/thumb/3/34/L%C3%A1ska_V%C3%A1clav01.jpg/220px-L%C3%A1ska_V%C3%A1clav01.jpg)
Václav Jan Láska (1862–1943) was a Czech surveyor, astronomer, geophysicist, and mathematician. He was based mainly at Charles University, and was the founding director (1920-1933) of the State Institute of Geophysics, which later became the Institute of Geophysics of the Czech Academy of Sciences.
Láska's empirical rule
[edit]This empirical rule is one way how to approximate the distance from an earthquake's epicenter. The rule is most fitting for distance in the range of 2 − 10 Mm (thousand km). The epicentral distance in thousands of km is roughly equal to the difference between arrival times of S and P waves in minutes minus 1.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Delta-Laska-english.png/220px-Delta-Laska-english.png)