Input files

The input directory contains model.nd, source_plane<m>.csv and obs_plane<n>.csv. Integer IDs match source_inds and obs_inds. CSV files contain numbers only, with no header and no index column.

Source patches

One row describes the center of a subfault.

Zero-based column	Quantity	Unit
0, 1	Latitude, longitude	Degrees; north/east positive
2	Depth	km, positive downward
3, 4, 5	Strike, dip, rake	Degrees
6, 7	Patch length along strike and dip	km
8	Final slip	m
9	Scalar seismic moment	N m
10 onward	Source time function samples	Relative shape, or moment rate

Selected source planes need the same number of STF columns. Pad shorter functions with zeros. The reader drops rows containing missing values, so a malformed row may disappear without an explicit schema error.

Dynamic synthesis resamples each STF to the CFS rate and rescales its discrete integral to column 9. A zero-integral function is skipped. Rupture delay is encoded by leading zero samples; the final CSV has no separate rupture-time column.

Static synthesis uses slip × patch area × local rigidity. Keep moment consistent with those values before comparing static and dynamic results. The original STF amplitude is not an additional moment multiplier.

Row order

For shape [n_strike, n_dip], dip varies fastest:

row = i_strike * n_dip + i_dip

The row count must equal the product of these dimensions. Calculations often operate directly on rows, but plotting reshapes them, so a wrong shape may only become apparent during visualization.

The low-level write_source_plane_csv converter accepts the opposite grid traversal: it reshapes (n_dip, n_strike), transposes, then flattens. Do not transpose its output again.

Observation faults

Every row contains six columns:

latitude, longitude, depth, strike, dip, rake

Coordinates follow the source conventions. Keep six columns for all modes: mode 0 uses the full mechanism; mode 1 uses strike/dip; mode 2 determines orientation from stress.

Rows follow obs_shapes, with dip varying fastest. Observation IDs need not match source IDs. Fixed-depth functions construct their own geographic grid, whereas run_all_* also calculates the selected observation faults.

Earth model

The bundled .nd files use:

depth_km  vp_km_per_s  vs_km_per_s  density_g_per_cm3  Qp  Qs

Single-word interface labels such as mantle appear in the supplied format. Repeated depths describe discontinuities. Preserve the full model needed by the chosen solver and travel-time calculation; earth_model_layer_num controls selection during preprocessing.

0.00   5.8000   3.4600   2.6000   927.34   599.99
20.00   5.8000   3.4600   2.6000   927.34   599.99
20.00   6.5000   3.8500   2.9000   927.34   599.99
35.00   6.5000   3.8500   2.9000   927.34   599.99
mantle
35.00   8.0400   4.4800   3.5020   636.00   417.59
77.50   8.0450   4.4900   3.5020   114.87    75.60
77.50   8.0505   4.5000   3.4268   115.30    76.06
120.00   8.0505   4.5000   3.4268   115.30    76.06
120.00   8.1750   4.5090   3.3711   118.37    76.55

The utility read_nd(path, with_Q=True) expects six numeric columns. Its default with_Q=False expects four; it does not remove Q columns automatically.

Convert a finite-fault model

from pathlib import Path
from dyncfs.convert_input_format import convert_fsp2source_csvs

input_dir = Path("my-case/input").resolve()
input_dir.mkdir(parents=True, exist_ok=True)
shapes = convert_fsp2source_csvs(
    path_fsp="complete_inversion.fsp",
    path_input_dir=str(input_dir),
    sampling_interval_stf=0.5,
    rise_ratio=0.5,
)
print(shapes)  # Copy into source_shapes.

FSP conversion requires LAT, LON, Z, SLIP, TRUP, RISE and SF_MOMENT. RAKE may fall back to the mechanism header. rise_ratio splits RISE between a triangular STF’s rising and falling parts; its range is [0, 1].

For USGS basic_inversion.param, use convert_usgs_basic2source_csvs. It converts cm to m and dyne cm to N m. Both converters write source CSVs and return segment shapes. Prepare receivers and the Earth model separately.

The Wenchuan and Ludian examples describe the supplied case files and their location-specific paths.