# [Seisunix] Modeling Covid-19 with Seismic Unix

Dominique ROUSSET dominique.rousset at univ-pau.fr
Mon Apr 6 09:18:49 CEST 2020

```Hi John,

SU is definitely full of unknown resources !!!

I hope everyone is as fine as possible, in these difficult times...

D.
PS
Don't forget that wiki.seismic-unix.org needs contributions !!!!
Ask me for an account to write in the wiki...

Le 05/04/2020 à 20:38, John Stockwell a écrit :
>
> I send my good wishes to all of you and I hope that you, your
> families, and your friends are faring well in this difficult time.
>
> For those who are interested in modeling populations, such as the
> current epidemic, there is a logistic equation solver called
> “verhulst” in the SU package which you may find of interest.
>
> For example for Covid-19 cases in the US, taking 22 January as day 0
> of cases in the US and 29 February as day 0 for deaths. Respective
> stepmax= values of 72 for cases and 34 for deaths are both 3 April
>
>
> verhulst stepmax=72 h=1 a1=.176 y0=1 a2=1e7 mode=x > calculated_cases.bin
>
> verhulst stepmax=35 h=1 a1=.268 y0=1 a2=1e6 mode=x > calculated_deaths.bin
>
> xgraph < calculated_cases.bin n=72 nplot=1 d1=1 &
>
> xgraph < calculated_deaths.bin n=34 nplot=1 d1=1 &
>
> The growth rate a1 values are determined empirically from publicly
> available data, in this case from the CDC and from the Worldometer
> site. You will have to make your own estimate of a1 for the data that
> you are modeling.
>
> Another parameter that is harder to get is an estimate of the carrying
> capacity of the system a2. Here I am assuming a maximum of 1 million
> cases in the US and 100 thousand deaths.
>
> The number of new cases or deaths per day is measured by the
> derivative of the solutions to the verhulst equation
>
> verhulst stepmax=72 h=1 a1=.176 y0=1 a2=1e7 mode=y > delta_cases.bin
>
> verhulst stepmax=35 h=1 a1=.268 y0=1 a2=1e6 mode=y > delta_deaths.bin
>
> xgraph < delta_cases.bin n=72 nplot=1 d1=1 &
>
> xgraph < delta_deaths.bin n=34 nplot=1 d1=1 &
>
> The peak in the change of the population per day occurs when the
> population reaches the exactly half of the carrying capacity of the
> system. Thus, raising the carrying capacity will increase the height
> of the peak and move it out later in time.
>
> Take care, everyone and stay safe.
>
> -John
>
> John Stockwell
> Visit: https://wiki.Seismic-Unix.org
> The new home of Seismic Un*x
>
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--
|Dominique Rousset           LFCR UMR5150 / E2S UPPA / Dpt des géosciences|
|Univ. Pau et des Pays de l'Adour BP 1155       F-64013 Pau Cedex - France|
|mailto:dominique.rousset at univ-pau.fr jami:drousset http://lfc.univ-pau.fr|
|Off: +33 559 407 423|Cell: +33 660 861 391|xmpp: dominique at rousset.nom.fr|

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