# Off fault receivers¶

## Introduction¶

Ascii receivers are enabled using the namelist output. Here is a commented example:

&Output
pickdt = 0.01 ! Pickpoint Sampling
pickDtType = 1 ! Pickpoint Type
nRecordPoints = 22 ! number of Record points which are read from file
RFileName = 'receivers.dat' ! Record Points in extra file
/


If pickDtType = 2, the output is generated every N time steps, where N is set by pickdt. If pickDtType = 1, output is generated every pickdt second.

receivers.dat is an ASCII file describing the coordinates of the receivers in the form:

x1 y1 z1
x2 y2 z2
(...)
xn yn zn


The receivers files contain the time-histories of the stress tensor (6 variables) and the particle velocities (3). Currently, there is no way to write only a subset of these variables.

## Placing free-surface receivers¶

Placing receivers on the free-surface requires special care when a realistic topography is used. The procedure to move receivers exactly to the surface is described here.

### compiling place_receivers on supermuc¶

module load netcdf/mpi
export PKG_CONFIG_PATH=$NETCDF_BASE/lib/pkgconfig/:$PKG_CONFIG_PATH
scons