If I want to measure deformation caused by an earthquake, what values should I use for the multilooking and Gaussian-filter parameters?

Below is the configuration I used to process the 2026 M7.5 Venezuela earthquake. The resulting interferogram shows relatively low coherence over much of the study area, which affects the quality of the retrieved deformation signal. What parameters or processing strategies would you recommend adjusting to improve the deformation results?

ISCE3 0.25.17 NISAR InSAR runconfig: 15x15 coherence-recovery branch.

Run from DInSAR_T54D: /home/syw/tools/miniforge/envs/isce3/bin/python3.13 -m nisar.workflows.insar runconfigs/frame083_4005_15x15_coh022.yaml

runconfig:
name: "T54D_frame083_4005_event_dinsar_15x15_coh022"
groups:
pge_name_group:
pge_name: INSAR_L_PGE
input_file_group:
reference_rslc_file: "../slcs/T54D/NISAR_L1_PR_RSLC_023_054_D_083_4005_DHDH_A_20260617T230235_20260617T230310_P05023_N_F_J_002.h5"
secondary_rslc_file: "../slcs/T54D/NISAR_L1_PR_RSLC_024_054_D_083_4005_DHDH_A_20260629T230235_20260629T230309_P05023_N_F_J_001.h5"
dynamic_ancillary_file_group:
dem_file: "../dem/Venezuela2026_NISAR_DEM_v1.2_EPSG4326_selected.tif"
dem_file_description: "NISAR DEM v1.2, EPSG:4326, WGS84 ellipsoid heights"
orbit_files:
reference_orbit_file: "../orbits/NISAR_ANC_J_PR_POE_20260702T171304_20260616T205942_20260618T025942.xml"
secondary_orbit_file: "../orbits/NISAR_ANC_J_PR_POE_20260715T185325_20260628T205942_20260630T025942.xml"
# tec_file is an optional IMAGEN TEC geolocation correction, not the
# split-spectrum ionosphere phase correction enabled below.
tec_file: null
troposphere_weather_model_files:
reference_troposphere_file: "../atmosphere/ERA5/weather/ERA5_N7_N15_W72_W65_20260617_23.grb"
secondary_troposphere_file: "../atmosphere/ERA5/weather/ERA5_N7_N15_W72_W65_20260629_23.grb"
product_path_group:
product_path: "products/frame083_4005_15x15_coh022"
scratch_path: "scratch/frame083_4005_15x15_coh022"
sas_output_file: "products/frame083_4005_15x15_coh022/_product.h5"
primary_executable:
product_type: RIFG_RUNW_GUNW
debug_level_group:
debug_switch: false
worker:
internet_access: false
gpu_enabled: true
gpu_id: 0
processing:
process_single_co_pol_offset: true
input_subset:
list_of_frequencies:
A: [HH]
geocode:
output_epsg: 4326
output_posting:
A:
x_posting: 0.000600000000
y_posting: 0.000600000000
wrapped_interferogram:
interp_method: SINC
output_posting:
A:
x_posting: 0.000600000000
y_posting: 0.000600000000
top_left:
y_abs: 10.70000000
x_abs: -68.25000000
bottom_right:
y_abs: 10.30000000
x_abs: -67.25000000
lines_per_block: 1000
interp_method: BILINEAR
bandpass:
lines_per_block: 1000
window_function: tukey
window_shape: 0.25
rdr2geo:
threshold: 1.0e-7
numiter: 25
extraiter: 10
lines_per_block: 1000
write_x: true
write_y: true
write_z: true
write_layover_shadow: true
geo2rdr:
threshold: 1.0e-8
maxiter: 25
lines_per_block: 1000
coarse_resample:
lines_per_tile: 1000
columns_per_tile: 1000
dense_offsets:
enabled: false
lines_per_block: 1000
window_range: 64
window_azimuth: 64
half_search_range: 20
half_search_azimuth: 20
skip_range: 32
skip_azimuth: 32
margin: 64
cross_correlation_domain: frequency
slc_oversampling_factor: 2
deramping_method: complex
deramping_axis: azimuth
use_gross_offsets: true
gross_offset_range: 0
gross_offset_azimuth: 0
merge_gross_offset: false
correlation_statistics_zoom: 21
correlation_surface_zoom: 8
correlation_surface_oversampling_factor: 64
correlation_surface_oversampling_method: fft
cuda_streams: 2
windows_batch_range: 10
windows_batch_azimuth: 5
offsets_product:
enabled: false
lines_per_block: 1000
skip_range: 15
skip_azimuth: 15
margin: 64
cross_correlation_domain: frequency
slc_oversampling_factor: 2
deramping_method: complex
deramping_axis: azimuth
use_gross_offsets: true
gross_offset_range: 0
gross_offset_azimuth: 0
merge_gross_offset: false
correlation_statistics_zoom: 21
correlation_surface_zoom: 8
correlation_surface_oversampling_factor: 64
correlation_surface_oversampling_method: sinc
cuda_streams: 2
windows_batch_range: 10
windows_batch_azimuth: 5
layer1:
cross_correlation_method: incoherent
window_range: 64
window_azimuth: 64
half_search_range: 16
half_search_azimuth: 16
rubbersheet:
enabled: false
fine_resample:
enabled: false
crossmul:
range_looks: 15
azimuth_looks: 15
flatten: true
oversample: 2
lines_per_block: 1024
common_band_range_filter: true
common_band_azimuth_filter: true
filter_interferogram:
lines_per_block: 100
filter_type: gaussian
gaussian:
sigma_range: 1.5
sigma_azimuth: 1.5
filter_size_range: 7
filter_size_azimuth: 7
phase_unwrap:
algorithm: snaphu
range_looks: 1
azimuth_looks: 1
preprocess_wrapped_phase:
enabled: true
mask:
mask_type: coherence
outlier_threshold: 0.22
filling_enabled: false
snaphu:
cost_mode: defo
initialization_method: mcf
min_conncomp_frac: 0.001
ntiles: [4, 4]
tile_overlap: [512, 512]
nproc: 1
single_tile_reoptimize: true
regrow_conncomps: true
baseline:
mode: top_bottom
ionosphere_phase_correction:
enabled: true
lines_per_block: 1000
spectral_diversity: main_diff_low_high_subband
list_of_frequencies:
A: [HH]
split_range_spectrum:
lines_per_block: 2048
window_function: tukey
window_shape: 0.25
dispersive_filter:
enabled: true
filter_mask_type: [coherence, connected_components]
filter_coherence_threshold: 0.22
filling_method: nearest
kernel_range: 150
kernel_azimuth: 150
sigma_range: 50
sigma_azimuth: 50
filter_iterations: 1
unwrap_correction: true
min_cluster_pixels: 2
bridge_algorithm_enabled: true
bridge_radius: 500
bridge_erosion_size: 2
bridge_minimum_samples: 14
troposphere_delay:
enabled: true
package: pyaps
weather_model_type: ERA5
delay_direction: line_of_sight_mapping
enable_wet_product: false
enable_hydrostatic_product: false
enable_comb_product: true
correction_luts:
solid_earth_tides_enabled: true
output:
page_enabled: true
compression_enabled: true
compression_level: 1
chunk_size: [512, 512]
shuffle: true
logging:
path: "logs/frame083_4005_15x15_coh022.log"
write_mode: a

Start with the supplied ISCE3 NISAR InSAR runconfig, focusing on crossmul multilooking and Gaussian interferogram filtering. Review the processing documentation and comparable configurations to determine how these parameters affect coherence and deformation retrieval. Done means providing justified parameter or processing recommendations supported by improved coherence and deformation results.